Information on EC 1.12.99.6 - hydrogenase (acceptor)

H2 + acceptor

H+ + reduced acceptor

H2 + acceptor

H+ + reduced acceptor

reaction mechanism

H2 + acceptor

H+ + reduced acceptor

2 different enzymes, hydrogenase I and II

H2 + acceptor

H+ + reduced acceptor

2 different enzymes, hydrogenase I and II

H2 + acceptor

H+ + reduced acceptor

methyl viologen acts as electron acceptor

Crocosphaera subtropica ATCC 51142

H2 + acceptor

H+ + reduced acceptor

B1WTU9

H2 + acceptor

H+ + reduced acceptor

Crocosphaera subtropica ATCC 51142 CCY 0110

H2 + acceptor

H+ + reduced acceptor

Crocosphaera subtropica ATCC 51142 PCC 7424

H2 + acceptor

H+ + reduced acceptor

Crocosphaera subtropica ATCC 51142 PCC 7425b

H2 + acceptor

H+ + reduced acceptor

Crocosphaera subtropica ATCC 51142 PCC 7822

H2 + acceptor

H+ + reduced acceptor

Crocosphaera subtropica ATCC 51142 PCC 8801

H2 + acceptor

H+ + reduced acceptor

Crocosphaera subtropica ATCC 51142 PCC 8802

H2 + acceptor

H+ + reduced acceptor

Crocosphaera watsonii WH8501

H2 + acceptor

H+ + reduced acceptor

H2 + acceptor

H+ + reduced acceptor

Q84GM3; Q4G6A7

H2 + acceptor

H+ + reduced acceptor

H2 + acceptor

H+ + reduced acceptor

Cronbergia siamensis SAG 11.82 TISTR 8012

H2 + acceptor

H+ + reduced acceptor

Cronbergia siamensis SAG 11.82 TISTR 8012

Q84GM3; Q4G6A7

H2 + acceptor

H+ + reduced acceptor

439633, 674448, 686733

H2 + acceptor

H+ + reduced acceptor

benzyl viologen acts as electron acceptor

Cylindrospermopsis raciborskii

H2 + acceptor

H+ + reduced acceptor

Cupriavidus necator H16 / ATCC 23440 / NCIB 10442 / S-10-1

674448, 686733

H2 + acceptor

H+ + reduced acceptor

Cylindrospermopsis raciborskii CS-505

H2 + acceptor

H+ + reduced acceptor

H2 + acceptor

H+ + reduced acceptor

H2 + acceptor

H+ + reduced acceptor

reaction mechanism

H2 + acceptor

H+ + reduced acceptor

methyl viologen acts as electron acceptor

H2 + acceptor

H+ + reduced acceptor

methyl viologen acts as electron acceptor

H2 + acceptor

H+ + reduced acceptor

methylene blue acts as electron acceptor

Desulfovibrio desulfuricans Norway

H2 + acceptor

H+ + reduced acceptor

methyl viologen acts as electron acceptor

Desulfovibrio desulfuricans Norway

H2 + acceptor

H+ + reduced acceptor

methylene blue acts as electron acceptor

H2 + acceptor

H+ + reduced acceptor

439638

H2 + acceptor

H+ + reduced acceptor

reaction mechanism

439638

H2 + acceptor

H+ + reduced acceptor

enzyme is more active in hydrogen evolution than in hydrogen uptake

H2 + acceptor

H+ + reduced acceptor

439637

H2 + acceptor

H+ + reduced acceptor

H2 + acceptor

H+ + reduced acceptor

reaction mechanism

Desulfovibrio vulgaris Hildenborough

H2 + acceptor

H+ + reduced acceptor

Desulfovibrio vulgaris Miyazaki F

H2 + acceptor

H+ + reduced acceptor

439637

H2 + acceptor

H+ + reduced acceptor

Desulfovibrio vulgaris Miyazaki F

reaction mechanism

H2 + acceptor

H+ + reduced acceptor

439630

H2 + acceptor

H+ + reduced acceptor

benzyl viologen, methylene blue and methylviologen can act as electron acceptors

H2 + acceptor

H+ + reduced acceptor

Frankia sp.

671937

H2 + acceptor

H+ + reduced acceptor

Gloeocapsa alpicola

Gloeocapsa alpicola CALU 743

H2 + acceptor

H+ + reduced acceptor

H2 + acceptor

H+ + reduced acceptor

Q841J7; Q84IJ8

H2 + acceptor

H+ + reduced acceptor

methylene blue acts as electron acceptor

H2 + acceptor

H+ + reduced acceptor

methylene blue, methyl viologen, methionaquinone, FMN and FAD can serve as electron acceptors, but not NAD+ or NADP+

H2 + acceptor

H+ + reduced acceptor

Hydrogenobacter thermophilus TK-6 / IAM 12695

methylene blue, methyl viologen, methionaquinone, FMN and FAD can serve as electron acceptors, but not NAD+ or NADP+

H2 + acceptor

H+ + reduced acceptor

Limnospira maxima

H2 + acceptor

H+ + reduced acceptor

Limnospira maxima CS-328

H2 + acceptor

H+ + reduced acceptor

Limnospira maxima FACHBSM

H2 + acceptor

H+ + reduced acceptor

H2 + acceptor

H+ + reduced acceptor

Lyngbya aestuarii CCY 9616

H2 + acceptor

H+ + reduced acceptor

H2 + acceptor

H+ + reduced acceptor

H2 + acceptor

H+ + reduced acceptor

H2 + acceptor

H+ + reduced acceptor

H2 + acceptor

H+ + reduced acceptor

H2 + acceptor

H+ + reduced acceptor

Megasphaera elsdenii

2 different enzymes, hydrogenase I and II

H2 + acceptor

H+ + reduced acceptor

benzyl viologen, methylene blue, ferredoxin and methylviologen can act as electron acceptors

H2 + acceptor

H+ + reduced acceptor

ferredoxin acts as physiological electron donor

H2 + acceptor

H+ + reduced acceptor

benzyl viologen, methylene blue, ferredoxin and methylviologen can act as electron acceptors

H2 + acceptor

H+ + reduced acceptor

ferredoxin acts as physiological electron donor

H2 + acceptor

H+ + reduced acceptor

Microcystis aeruginosa

Microcystis aeruginosa NIES-843

H2 + acceptor

H+ + reduced acceptor

H2 + acceptor

H+ + reduced acceptor

Nostoc punctiforme

H2 + acceptor

H+ + reduced acceptor

H2 + acceptor

H+ + reduced acceptor

Q3C1T8; Q3C1T9

H2 + acceptor

H+ + reduced acceptor

Q3C1T8, Q8YZ11

H2 + acceptor

H+ + reduced acceptor

H2 + acceptor

H+ + reduced acceptor

Q8YZ11

H2 + acceptor

H+ + reduced acceptor

Nostoc sp. PCC 7422

Q3C1T8

H2 + acceptor

H+ + reduced acceptor

enzyme acts on artificial electron-accepting dyes, but is ineffective with pyridine nucleotides or other soluble physiological electron acceptors

Prochlorothrix hollandica

H2 + acceptor

H+ + reduced acceptor

H2 + acceptor

H+ + reduced acceptor

benzyl viologen, methyl viologen, NADPH and NADH can serve as electron donors

H2 + acceptor

H+ + reduced acceptor

methyl viologen acts as electron acceptor

H2 + acceptor

H+ + reduced acceptor

methylene blue acts as electron acceptor

H2 + acceptor

H+ + reduced acceptor

reduced ferredoxin can act as acceptor

H2 + acceptor

H+ + reduced acceptor

ferredoxin acts as physiological electron donor

H2 + acceptor

H+ + reduced acceptor

Raphidiopsis brookii

H2 + acceptor

H+ + reduced acceptor

Raphidiopsis brookii D9

H2 + acceptor

H+ + reduced acceptor

Salmonella enterica

Hya can oxidize both exogenously added H2 and formate hydrogen lyase-evolved H2 anaerobically

Salmonella enterica JSG210, serovar Typhimurium

H2 + acceptor

H+ + reduced acceptor

Hya can oxidize both exogenously added H2 and formate hydrogen lyase-evolved H2 anaerobically

H2 + acceptor

H+ + reduced acceptor

Streptomyces sp.

711862

H2 + acceptor

H+ + reduced acceptor

Streptomyces sp. PCB7

711862

H2 + acceptor

H+ + reduced acceptor

Synechococcus elongatus

Synechococcus elongatus PCC 7942

H2 + acceptor

H+ + reduced acceptor

H2 + acceptor

H+ + reduced acceptor

Synechocystis sp.

H2 + acceptor

H+ + reduced acceptor

benzyl viologen acts as electron acceptor

H2 + acceptor

H+ + reduced acceptor

methyl viologen acts as electron acceptor

H2 + acceptor

H+ + reduced acceptor

H2 + acceptor

H+ + reduced acceptor

Q9ZAK2

H2 + acceptor

H+ + reduced acceptor

methyl viologen and benzyl viologen can serve as electron acceptors

H2 + acceptor

H2-acceptor

H2 + acceptor

H2-acceptor

Clostridium butyricum

Q1KPU9

684596

H2 + acceptor

H2-acceptor

Clostridium butyricum M1

Q1KPU9

684596

H2 + Cr6+

Cr3+ + H+

H2 + Cr6+

Cr3+ + H+

H2 + Cr6+

Cr3+ + H+

H2 + methenyltetrahydromethanopterin

H+ + methylenetetrahydromethanopterin

the heterolytic cleavage of H2 by the enzyme is dependent on the presence of methenyltetrahydromethanopterin

H2 + methenyltetrahydromethanopterin

H+ + methylenetetrahydromethanopterin

the presence of methenyltetrahydromethanopterin is essentially required for H2 activation by [Fe] hydrogenase

H2 + methionaquinone

methionaquinol + H+

H2 + methionaquinone

methionaquinol + H+

Hydrogenobacter thermophilus TK-6 / IAM 12695

H2 + methyl viologen

H+ + reduced methyl viologen

725206

H2 + methyl viologen

H+ + reduced methyl viologen

H2 + methyl viologen

H+ + reduced methyl viologen

H2 + NADPH

NADP + H+

Pyrococcus furiosus MW0430

H2 + NADPH

NADP + H+

H2 + O2

713401

H2 + O2

Cupriavidus necator H16 / ATCC 23440 / NCIB 10442 / S-10-1

713401

H2 + O2

Salmonella enterica

Salmonella enterica JSG210, serovar Typhimurium

H2 + O2

H2 + oxidized acceptor

H+ + reduced acceptor

almost 100% of the membrane-attached MBH is reversibly redox-active

H2 + oxidized acceptor

H+ + reduced acceptor

[NiFeSe]-hydrogenase is a highly efficient H2 cycling catalyst

H2 + oxidized acceptor

H+ + reduced acceptor

heterolytic H2 cleavage, with one hydrogen ending up as a bridging hydride and one as a proton on a cysteine ligand, which has a barrier slightly too high to be compatible with measured catalytic turnover rates. Alternative mechanisms suggest heterolytic cleavage as an initial step to generate a complex with nickel in oxidation state Ni(I). In the following cycles, H2 is instead cleaved on nickel using an oxidative addition mechanism with a lower barrier

702254

H2 + oxidized acceptor

H+ + reduced acceptor

Shewanella decolorationis

704016

H2 + oxidized acceptor

H+ + reduced acceptor

uncultured bacterium

Q2PWI0, Q2PWI3, Q2PWI4, Q2PWI5, Q2PWI6, Q2PWI7, Q2PWI9, Q2PWJ0, Q2PWJ8, Q38IH5, Q38IH6, Q38IH8, Q38IH9, Q38II3, Q38II4, Q38IJ1

701778

H2 + oxidized amaranth

H+ + reduced amaranth

684651

H2 + oxidized amaranth

H+ + reduced amaranth

Shewanella decolorationis S12

684651

H2 + oxidized benzyl viologen

H+ + reduced benzyl viologen

439648, 686732, 702218

H2 + oxidized benzyl viologen

H+ + reduced benzyl viologen

H2 + oxidized benzyl viologen

H+ + reduced benzyl viologen

H2 + oxidized benzyl viologen

H+ + reduced benzyl viologen

H2 + oxidized benzyl viologen

H+ + reduceded benzyl viologen

Desulfomicrobium baculatum 9974

H2 + oxidized benzyl viologen

H+ + reduceded benzyl viologen

H2 + oxidized benzyl viologen

H+ + reduceded benzyl viologen

Thiocapsa roseopersicina Bbs

H2 + oxidized benzyl viologen

H+ + reduceded benzyl viologen

H2 + oxidized benzyl viologen

reduced benzyl viologen + H+

H2 + oxidized benzyl viologen

reduced benzyl viologen + H+

H2 + oxidized benzyl viologen

reduced benzyl viologen + H+

Dehalococcoides mccartyi

657605

H2 + oxidized benzyl viologen

reduced benzyl viologen + H+

H2 + oxidized benzyl viologen

reduced benzyl viologen + H+

there is at least one autocatalytic reaction step in the hydrogenase-catalyzed reaction

672638

H2 + oxidized benzyl viologen

reduced benzyl viologen + H+

659355

H2 + oxidized dichloroindophenol

H+ + reduced dichloroindophenol

H2 + oxidized dichloroindophenol

H+ + reduced dichloroindophenol

H2 + oxidized electron acceptor

H+ + reduced electron acceptor

H2 + oxidized electron acceptor

H+ + reduced electron acceptor

both platinum and pyrolytic graphite edge/HydA electrodes are effective catalysts operating near the reversible potential of the H+/H2 redox couple

H2 + oxidized electron acceptor

H+ + reduced electron acceptor

704015

H2 + oxidized electron acceptor

H+ + reduced electron acceptor

Desulfovibrio vulgaris str. Hildenborough

H2 + oxidized electron acceptor

H+ + reduced electron acceptor

H2 + oxidized electron acceptor

H+ + reduced electron acceptor

704012

H2 + oxidized ferredoxin

reduced ferredoxin

H2 + oxidized ferredoxin

reduced ferredoxin

H2 + oxidized methionaquinone

reduced methionaquinone

H2 + oxidized methionaquinone

reduced methionaquinone

Hydrogenobacter thermophilus TK-6 / IAM 12695

H2 + oxidized methyl viologen

H+ + reduced methyl viologen

H2 + oxidized methyl viologen

H+ + reduced methyl viologen

Aeropyrum camini SY1 / ATCC BAA-758 / DSM 16960 / JCM 2091

H2 + oxidized methyl viologen

H+ + reduced methyl viologen

H2 + oxidized methyl viologen

H+ + reduced methyl viologen

H2 + oxidized methyl viologen

H+ + reduced methyl viologen

H2 + oxidized methyl viologen

H+ + reduced methyl viologen

H2 + oxidized methyl viologen

H+ + reduced methyl viologen

Methanococcus maripaludis

H2 + oxidized methyl viologen

H+ + reduced methyl viologen

Methanothermococcus thermolithotrophicus

H2 + oxidized methyl viologen

H+ + reduced methyl viologen

H2 + oxidized methyl viologen

H+ + reduced methyl viologen

Methanotorris igneus

H2 + oxidized methyl viologen

H+ + reduced methyl viologen

H2 + oxidized methyl viologen

H+ + reduced methyl viologen

Tetraselmis sp. KSN-2002 NCIM 1605

Thermoanaerobacterium saccharolyticum

H2 + oxidized methyl viologen

H+ + reduced methyl viologen

704309

H2 + oxidized methyl viologen

reduced methyl viologen + H+

H2 + oxidized methyl viologen

reduced methyl viologen + H+

658972

H2 + oxidized methyl viologen

reduced methyl viologen + H+

Dehalococcoides mccartyi

657605

H2 + oxidized methyl viologen

reduced methyl viologen + H+

H2 + oxidized methyl viologen

reduced methyl viologen + H+

657622, 659310, 659520

H2 + oxidized methyl viologen

reduced methyl viologen + H+

Enterobacter cloacae IIT-BT 08

H2 + oxidized methyl viologen

reduced methyl viologen + H+

Enterobacter cloacae

657778

H2 + oxidized methyl viologen

reduced methyl viologen + H+

657778

H2 + oxidized methyl viologen

reduced methyl viologen + H+

Klebsiella aerogenes

672729

H2 + oxidized methyl viologen

reduced methyl viologen + H+

H2 + oxidized methylene blue

H+ + reduced methylene blue

H2 + oxidized methylene blue

H+ + reduced methylene blue

H2 + oxidized methylene blue

H+ + reduced methylene blue

H2 + oxidized methylene blue

H+ + reduced methylene blue

H2 + oxidized methylene blue

H+ + reduced methylene blue

H2 + oxidized methylene blue

reduced methylene blue

H2 + oxidized methylene blue

reduced methylene blue

H2 + oxidized methylene blue

reduced methylene blue

Acidithiobacillus ferrooxidans

H2 + oxidized methylene blue

reduced methylene blue + H+

674936

H2 + oxidized methylene blue

reduced methylene blue + H+

H2 + oxidized methylene blue

reduced methylene blue + H+

H2 + oxidized sodium hydrosulfite

H+ + reduced sodium hydrosulfite

H2 + oxidized sodium hydrosulfite

H+ + reduced sodium hydrosulfite

reduced ferredoxin

H2 + oxidized ferredoxin

reduced ferredoxin

H2 + oxidized ferredoxin

additional information

although the HoxF subunit contains binding sites for flavin mononucleotide and NAD(H), cell-free extracts of Allochromatium vinosum does not catalyse a H2-dependent reduction of NAD+

674938

additional information

the catalytic bias, i.e. the ratio of maximal rates in the two directions is not mainly determined by redox properties of the active site, but rather by steps which occur on sites of the proteins that are remote from the active site

725206

additional information

the enzyme exhibits both proton-reducing and H2-oxidizing activities

additional information

no activity is observed using NAD+, 2,3-dimethoxy methyl-1,4-benzoquinone, and potassium ferricyanide as electron acceptors

additional information

no activity is observed using NAD+, 2,3-dimethoxy methyl-1,4-benzoquinone, and potassium ferricyanide as electron acceptors

additional information

a diiron dithiolate complex holding a micro-hydride on the iron atoms and a proton on the basic site of a chelating diphosphine ligand as a structural model of the [FeFe]-hydrogenase active site. The pendant base in the phosphine ligand may play a similar role to the proton-transfer relay as the bridging N in a diiron azadithiolate complex does

703184

additional information

oxidation of hexacarbonyl(1,3-dithiolato-S,S')diiron complexes with varying amounts of dimethyldioxirane as mimics of the active site of [FeFe]-hydrogenase. Chemoselectivity of the oxidation products depends upon the substituent R (R=H, Me, 1/2 (CH2)5)

703152

additional information

protonation of a model of the subsite of [FeFe]-hydrogenase, [Fe2(micro-pdt)(CO)4(PMe3)2]. The deceptively simple stoichiometric reaction is limited by the rate of protonation of the basal-apical isomer followed by its rearrangement to the transoid basal form

703182

additional information

study on the catalytic mechanism of an active-site model of [Fe] hydrogenase by small modifications of the first ligand shell. Dispersion interactions between the active site and the hydride acceptor methenyltetrahydromethanopterin render the hydride transfer step less endergonic and lower its barrier. Substitution of CO by CN-, which resembles [FeFe] hydrogenase-like coordination, inverts the elementary steps H- transfer and H2 cleavage. The catalytic efficiency of [Fe] hydrogenase can be attributed to a flat energy profile throughout the catalytic cycle. Intermediates that are too stable, as they occur, e.g., when one CO ligand is substituted by CN-, significantly slow down the turnover rate of the enzyme. The catalytic activity of the wild-type form of the active-site model could, however, be enhanced by a PH3 ligand substitution of the CO ligand

725788

additional information

hydrogenase during its reaction cycle has an autocatalytic step

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NATURAL SUBSTRATE

NATURAL PRODUCT

REACTION DIAGRAM

ORGANISM

UNIPROT

COMMENTARY
(Substrate)

LITERATURE
(Substrate)

COMMENTARY
(Product)

LITERATURE
(Product)

REVERSIBILITY
r=reversible
ir=irreversible
?=not specified

H2 + acceptor

acceptor-H2

H2 + acceptor

acceptorH2

H2 + acceptor

H+ + reduced acceptor

48 entries

H2 + acceptor

reduced acceptor

742652

H2 + methylene blue

reduced methylene blue

742265

H2 + NADPH

NADP + H+

H2 + acceptor

acceptor-H2

658987

H2 + acceptor

acceptor-H2

Q7WT77, Q7WT78, Q7WT79, Q7WT80, Q7WT81, Q7WT82

657739

H2 + acceptor

acceptorH2

H2 + acceptor

acceptorH2

Candidatus Atelocyanobacterium thalassa

Q841J7, Q841J8

659887

H2 + acceptor

H+ + reduced acceptor

Bradyrhizobium sp.

671432

H2 + acceptor

H+ + reduced acceptor

D3EMX6

H2 + acceptor

H+ + reduced acceptor

reaction mechanism

H2 + acceptor

H+ + reduced acceptor

2 different enzymes, hydrogenase I and II

Crocosphaera subtropica ATCC 51142

H2 + acceptor

H+ + reduced acceptor

B1WTU9

H2 + acceptor

H+ + reduced acceptor

Crocosphaera subtropica ATCC 51142 CCY 0110

H2 + acceptor

H+ + reduced acceptor

Crocosphaera subtropica ATCC 51142 PCC 7424

H2 + acceptor

H+ + reduced acceptor

Crocosphaera subtropica ATCC 51142 PCC 7425b

H2 + acceptor

H+ + reduced acceptor

Crocosphaera subtropica ATCC 51142 PCC 7822

H2 + acceptor

H+ + reduced acceptor

Crocosphaera subtropica ATCC 51142 PCC 8801

H2 + acceptor

H+ + reduced acceptor

Crocosphaera subtropica ATCC 51142 PCC 8802

H2 + acceptor

H+ + reduced acceptor

H2 + acceptor

H+ + reduced acceptor

Cronbergia siamensis SAG 11.82 TISTR 8012

Cylindrospermopsis raciborskii

H2 + acceptor

H+ + reduced acceptor

Cylindrospermopsis raciborskii CS-505

H2 + acceptor

H+ + reduced acceptor

H2 + acceptor

H+ + reduced acceptor

reaction mechanism

H2 + acceptor

H+ + reduced acceptor

reaction mechanism

439638

H2 + acceptor

H+ + reduced acceptor

reaction mechanism

Desulfovibrio vulgaris Miyazaki F

H2 + acceptor

H+ + reduced acceptor

reaction mechanism

H2 + acceptor

H+ + reduced acceptor

Gloeocapsa alpicola

Gloeocapsa alpicola CALU 743

H2 + acceptor

H+ + reduced acceptor

H2 + acceptor

H+ + reduced acceptor

Limnospira maxima

H2 + acceptor

H+ + reduced acceptor

Limnospira maxima CS-328

H2 + acceptor

H+ + reduced acceptor

Limnospira maxima FACHBSM

H2 + acceptor

H+ + reduced acceptor

Lyngbya aestuarii CCY 9616

H2 + acceptor

H+ + reduced acceptor

H2 + acceptor

H+ + reduced acceptor

H2 + acceptor

H+ + reduced acceptor

H2 + acceptor

H+ + reduced acceptor

H2 + acceptor

H+ + reduced acceptor

H2 + acceptor

H+ + reduced acceptor

ferredoxin acts as physiological electron donor

H2 + acceptor

H+ + reduced acceptor

ferredoxin acts as physiological electron donor

H2 + acceptor

H+ + reduced acceptor

Microcystis aeruginosa

Microcystis aeruginosa NIES-843

H2 + acceptor

H+ + reduced acceptor

H2 + acceptor

H+ + reduced acceptor

Nostoc punctiforme

H2 + acceptor

H+ + reduced acceptor

H2 + acceptor

H+ + reduced acceptor

Q3C1T8, Q8YZ11

H2 + acceptor

H+ + reduced acceptor

H2 + acceptor

H+ + reduced acceptor

Q8YZ11

H2 + acceptor

H+ + reduced acceptor

Nostoc sp. PCC 7422

Q3C1T8

Prochlorothrix hollandica

H2 + acceptor

H+ + reduced acceptor

H2 + acceptor

H+ + reduced acceptor

ferredoxin acts as physiological electron donor

H2 + acceptor

H+ + reduced acceptor

Raphidiopsis brookii

H2 + acceptor

H+ + reduced acceptor

Raphidiopsis brookii D9

H2 + acceptor

H+ + reduced acceptor

Synechococcus elongatus

Synechococcus elongatus PCC 7942

H2 + acceptor

H+ + reduced acceptor

H2 + acceptor

H+ + reduced acceptor

Synechocystis sp.

H2 + acceptor

H+ + reduced acceptor

Q9ZAK2

H2 + NADPH

NADP + H+

Pyrococcus furiosus MW0430

H2 + NADPH

NADP + H+

show all columns Go to Cofactor Search

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COFACTOR

ORGANISM

UNIPROT

COMMENTARY

LITERATURE

IMAGE

4Fe-4S-center

7 entries

FAD

FMN

heme b

involved in electron transport

iron-sulfur center

iron-sulfur centre

NAD+

[2Fe-2S]-center

[4Fe-4S]-center

additional information

iron-guanylylpyridinol

4Fe-4S-center

Anabaena sp.

contains two [4Fe-4S] clusters

4Fe-4S-center

contains two [4Fe-4S] clusters

4Fe-4S-center

contains two [4Fe-4S] clusters

4Fe-4S-center

contains two [4Fe-4S] clusters

4Fe-4S-center

Q3C1T8; Q3C1T9

contains two [4Fe-4S] clusters

4Fe-4S-center

Q841J7; Q84IJ8

contains two [4Fe-4S] clusters

4Fe-4S-center

Q84GM3; Q4G6A7

contains two [4Fe-4S] clusters

FAD

FAD

0.83 mol FAD per enzyme

iron-sulfur centre

contains a mononuclear iron coordinated by the sulfur of cysteine 176, the iron center is the catalytically active constituent of an iron guanylyl pyridone cofactor

iron-sulfur centre

contains one [2Fe-2S] and three [4Fe-4S] clusters

iron-sulfur centre

P31891

data from crystal structure

726038

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METALS and IONS

ORGANISM

UNIPROT

COMMENTARY

LITERATURE

CN-

Fe2+

Iron

0.0025 mmol Mo per g protein

29 entries

Ni2+

8 entries

selenium

[NiFeSe]-hydrogenase

Sulfide

7 entries

additional information

Alteromonas macleodii

no increase in the hydrogenase activity is observed in response to ferric sulfate, ferric citrate, ferric ammonium citrate, and ferric nitrate

710951

CN-

the auxiliary proteins HoxL and HoxV assist in assembly of the Fe(CN-)2CO moiety

CN-

the catalytic center is equipped with 1.8 CN- per protein molecule

CN-

contains two CN- molecules at the active site

the auxiliary proteins HoxL and HoxV assist in assembly of the Fe(CN-)2CO moiety

the catalytic center is equipped with one CO

0.134 mmol Fe per g protein

Acidithiobacillus ferrooxidans

uptake [NiFe] hydrogenase

674936

NiFe-hydrogenase

658987

contains bimetallic center in active site

contains Fe-s clusters

enzyme contains Ni-Fe center and Fe-S clusters

658972

Ni-Fe active site. Presence of eight Fe-S clusters, three [2Fe-2S] clusters and five [4Fe-4S] clusters

674938

FeFe-hydrogenase

671932

HydADELTAEFG binds a [4Fe-4S] cluster

lacks the ferredoxin-like clusters, but contains the H-cluster [Fe4S4] component

the HydA1 H-cluster consists of a [4Fe4S] cluster and a diiron site, 2FeH

4Fe-4S clusters

iron-sulfur cluster as well as 4Fe-4S-ferredoxin-type cluster

4Fe-4S cluster

the large subunit HoxC is purified without its small subunit. Two forms of HoxC are identified. Both forms contain iron but only substoichiometric amounts of nickel. One form is a homodimer of HoxC whereas the second also contains the NiâFe site maturation proteins HypC and HypB. Despite the presence of the NiâFe active site in some of the proteins, both forms, which lack the FeâS clusters normally present in hydrogenases, cannot activate hydrogen. The incomplete insertion of nickel into the NiâFe site provides direct evidence that Fe precedes Ni in the course of metal center assembly

673617

is composed of a small subunit, capable in coordinating one [3Fe4S] and two [4Fe4S] clusters

the auxiliary proteins HoxL and HoxV assist in assembly of the Fe(CN-)2CO moiety

[NiFeSe]-hydrogenase, absence of a [3Fe-4S] cluster

contains several [4Fe-4S] clusters

4Fe-4S clusters

3Fe-xS and 4Fe-4S clusters

14 atoms per molecule, 2 4Fe-4S clusters

[FeFe]-hydrogenase.The H cluster (hydrogen-activating cluster) contains a di-iron centre ([2Fe]H subcluster, a (L)(CO)(CN)Fe(mu-RS2)(mu-CO)Fe (CysS)(CO)(CN) group) covalently attached to a cubane iron-sulphur cluster ([4Fe-4S]H subcluster). The added redox equivalent not only affects the [4Fe-4S]H subcluster, but also the di-iron centre

674923

contains FeNi-center

contains Ni-Fe bimetallic center as active site

659520

contains several [4Fe-4S] clusters

Q7WT77, Q7WT78, Q7WT79, Q7WT80, Q7WT81, Q7WT82

NiFe-hydrogenase

657739

11 atoms per mol enzyme

10.6 atoms per mol enzyme

iron-sulfur cluster as well as 4Fe-4S-ferredoxin-type cluster

contains several [4Fe-4S] clusters

hydrogen bonding affects the [NiFe] active site

675615

[NiFe] hydrogenase

677151

specific protein-protein interactions of maturation proteins may be required during [FeFe] cluster synthesis and/or insertion. Maturation proteins HydE and HydG interact with the [FeFe] hydrogenase large subunit HydA, which binds the H-cluster. Neither HydE nor HydG interact with the [FeFe] hydrogenase small subunit, HydB. No interaction of HydF, which catalyzes an energy-dependent step during H-cluster assembly or insertion, with either HydA or HydB

702813

the Hred form is assigned as a mixture of an Fe(I)Fe(I) form with an open site on the distal iron center and either a Fe(I)Fe(I) form in which the distal cyanide is protonated or a Fe(II)Fe(II) form with a bridging hydride ligand. The Hox form is assigned as a valence-localized Fe(I)Fe(II) redox level with an open site at the distal iron. The Hox air form is assigned as an Fe(II)Fe(II) redox level with OH- or OOH- bound to the distal iron center that may or may not have an oxygen atom bound to one of the sulfur atoms of the dithiolate linker

two ferredoxin-like [Fe4S4] clusters

Desulfovibrio vulgaris str. Hildenborough

Fe-hydrogenase

12.2 mol per mol enzyme, iron-sulfur protein

10.9 mol per tetramer, 3Fe-4S cluster

membrane-bound [NiFe]-hydrogenase exhibits prominent electron paramagnetic resonance signals originating from [3Feâ4S]1 and [4Feâ4S]1 clusters

Megasphaera elsdenii

iron-sulfur cluster as well as 4Fe-4S-ferredoxin-type cluster

iron center octahedrally coordinated by one dithiothreitol-sulfur and one dithiothreitol-oxygen, two CO, the nitrogen of 2-pyridinol and the 6-formylmethyl group of 2-pyridinol in an acyliron ligation

11.3 mol per mol of enzyme

7.3 mol per enzyme

21 atoms per mol enzyme, 5 4Fe-4S cluster and 1 2Fe-2S cluster

31 g iron per 185 g enzyme

iron azadithiolate phosphine-substituted complex and its protonated species featuring the NH proton and/or bridging Fe hydride, [Fe2(micro-S(CH2)2NnPr(H)m(CH2)2S)(micro-H)n(CO)4(PMe3)2]2 (2m+2n)+, mimic the active site of Fe-only hydrogenase. The ability to accept protons for the aza nitrogen and the Fe sites is essential for the enzymatic H2 production at the mild potential

704016

protonation can take place in a terminal fashion at a single Fe or by bridging between two iron centres, protonation of a model of the subsite of [FeFe]-hydrogenase, [Fe2(m-pdt)(CO)4(PMe3)2], occurs via a two-step mechanism

703182

protonation of diiron dithiolato complexes can occur at a single Fe site, even for symmetrical (FeI)2 compounds. The terminal hydride [HFe2(S2C3H6)(CO)2(dppv)2]+ catalyzes proton reduction at potentials 200 mV milder than the isomeric bridging hydride, thereby establishing a thermodynamic advantage for catalysis operating via terminal hydride

704012

the Fe(CO)2(Pi-Pr3) site is rotated in solution, driven by steric factors. Fe atom featuring a vacant apical coordination position is an electrophilic Fe(I) center. One-electron oxidation of [Fe2(S2C2H4)(CN)(CO)3(dppv)]- results in 2e oxidation of 0.5 equiv to give the micro-cyano derivative [FeI2(S2C2H4)(CO)3(dppv)](micro-CN)[FeII2(S2C2H4)(micro-CO)(CO)2(CN)(dppv)]

704014

has Fe-S clusters, contains 10 g atoms of Fe per mol of protein

7-8 atoms per mol enzyme, 3Fe-4S cluster

contains several [4Fe-S] and [2Fe-2S] cluster

659523

[FeS] cluster

the electron acceptor interacts only with the [FeS]distal cluster in the hydrogenase, and accordingly the autocatalyst is a hydrogenase form in which the [FeS]distal cluster holds an electron (i.e., at least the [FeS]distal cluster is reduced)

4Fe-4S and 2Fe-2S clusters

FeNi-hydrogenase

659355

Fe2+

Alteromonas macleodii

essential element for the assembly and maturation, the addition of Fe-EDTA (0.05 mM) does not affect the level of hydrogenase activity

710951

Fe2+

1 mM increases hydrogenase activity 4fold, is not sufficient to increase hydrogenase activities without S-adenosyl methionine and the standard 20 L-amino acids

Fe2+

the active site has a characteristic bis(micro-thiolato)NiFe unit, where the Ni atom and the Fe atom are bridged by an undetermined oxygen-bearing ligand. This ligand probably derives from the aqueous solvent and is therefore most likely to be H2O, OH- or O2-. A NiFe complex is not able to activate H2 when coordinated with an CH3CN ligand, thus a highly labile ligand that is simultaneously able to act as a Lewis base for the heterolytic activation of H2 is crucial to the action of H2ase. The CH3CN-coordinated Ni(II)Fe(II) complex is unstable in the presence of water and decomposed to the Ni(II) complex and the Fe(II) complex via the Fe-S bond cleavage in water. In order to synthesise H2O-coordinated NiFe complexes in aqueous media, the Lewis acidity of the Fe centre must be increased to form strong Fe-S bonds. Thus, organometallic ligands with a back-donating character to form Fe-C bonds are required

703360

Fe2+

contains a Fe2+-binding site

684648

Iron

within the catalytic centre one carbonyl and two cyanide ligands are covalently attached to the iron

686733

Iron

the enzyme harbors an iron-containing cofactor, in which a lowspin iron is complexed by a pyridone, two CO and a cysteine sulfur, [Fe] hydrogenase apoenzyme is converted completely into [Fe] hydrogenase holoenzyme by mixing the apoenzyme with a 3fold excess of the iron-containing [Fe] hydrogenase cofactor

Thermococcus kodakarensis

Iron

Q8NKS2

contains 0.23 Fe atoms per molecule of large subunit HyhL

724185

0.0025 mmol Ni per g protein

Acidithiobacillus ferrooxidans

uptake [NiFe] hydrogenase

674936

NiFe-hydrogenase

658082, 658987

contains bimetallic center in active site

enzyme contains Ni-Fe center

658972

Ni-Fe active site

674938

NiFe-hydrogenase

contains Ni in the catalytic center

contains FeNi-center

contains Ni in the catalytic center

contains Ni-Fe bimetallic center as active site

Q7WT77, Q7WT78, Q7WT79, Q7WT80, Q7WT81, Q7WT82

NiFe-hyrogenase

657739

0.9 atoms per mol enzyme

0.9 atoms per mol enzyme

hydrogen bonding affects the [NiFe] active site

675615

[NiFe] hydrogenase has two different oxidized states, Ni-A (unready, exhibits a lag phase in reductive activation) and Ni-B (ready). Ni-B possesses a monatomic nonprotein bridging ligand at the Ni-Fe active site, whereas Ni-A has a diatomic species

677151

NiFe-hydrogenase

439630

NiFe-hydrogenase

1.06 mol per tetramer

0.9 mol per mol of enzyme

0.725 mol per enzyme

0.9 atoms per mol enzyme

31 g nickel per 185 g enzyme

Rhizobium leguminosarum

Rhizobium leguminosarum biovar viciae symbiotic hydrogenase activity and processing are limited by the level of nickel in agricultural soils

671433

contains 1 g of atom of Ni per mol of protein

0.6-0.7 atoms per mol enzyme

FeNi-hydrogenase

659355

Ni2+

Alteromonas macleodii

essential element for the assembly and maturation, addition of 0.1 mM Ni2+ to the growth medium significantly enhances the hydrogenase activity. Nickel-treatment affects the level of the protein, but not the mRNA

710951

Ni2+

is composed of a large subunit, harboring the [NiFe] active site

Ni2+

Ni-Fe active site assembly, nickel is absent in samples of HoxV

Ni2+

[NiFeSe]-hydrogenase

Ni2+

702254

Ni2+

the active site has a characteristic bis(micro-thiolato)NiFe unit, where the Ni atom and the Fe atom are bridged by an undetermined oxygen-bearing ligand. This ligand probably derives from the aqueous solvent and is therefore most likely to be H2O, OH- or O2-. A NiFe or NiRu complex are not able to activate H2 when coordinated with an CH3CN ligand, thus a highly labile ligand that is simultaneously able to act as a Lewis base for the heterolytic activation of H2 is crucial to the action of H2ase. The CH3CN-coordinated Ni(II)Fe(II) complex is unstable in the presence of water and decomposed to the Ni(II) complex and the Fe(II) complex via the Fe-S bond cleavage in water. In order to synthesise H2O-coordinated NiFe complexes in aqueous media, the Lewis acidity of the Fe centre must be increased to form strong Fe-S bonds. Thus, organometallic ligands with a back-donating character to form Fe-C bonds are required

703360

Ni2+

contains a Ni2+-binding site

684648

Ni2+

accessory protein HypB is necessary for Ni(II) incorporation into the hydrogenase protein. HypB has two metal-binding sites, a high-affinity Ni(II) site that includes ligands from the N-terminal domain and a low-affinity metal site located within the C-terminal GTPase domain

702218

Sulfide

14.4 atoms per molecule

Sulfide

10 atoms labile sulfide per mol enzyme

Sulfide

12 atoms acid labile sulfur atoms per mol enzyme

Sulfide

9.1 mol per mol enzyme, iron-sulfur protein

Sulfide

10.8 mol acid labile sulfur per mol of enzyme

Sulfide

7.2 mol labile sulfide per enzyme

Sulfide

24 g acid labile sulfide per 185 g enzyme

show all columns Go to Inhibitor Search

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INHIBITOR

ORGANISM

UNIPROT

COMMENTARY

LITERATURE

IMAGE

1-ethyl-3-(3-dimethylaminopropyl) carbodiimide

8 residues modified by 0.5 mM in the presence of 30 mM nitrotyrosine ethylester

5-5'dithiobis-(2-nitrobenzoate)

chemical modification of cysteine residues, 8 residues modified by 0.5 mM. 16 residues modified in the presence of 2% sodium dodecyl sulfate. 20 residues modified by 1 mM and in the presence of urea, EDTA, NaBH4

Carbonyl cyanide m-chlorophenylhydrazone

Cd2+

reversible inhibition

Cr3+

Cr6+

Cu2+

cyanide

diethyldicarbonate

65% loss of activity 6 mM

inhibits hydrogen production

674190

Hg2+

complete inhibition at 1 mM

Mg2+

reversible inhibition

N-bromosuccinimide

complete inactivation at 10 mM, 20% inactivation at 0.1 mM

Ni2+

competitive vs. Oxidized methyl viologen

nitrite

70% loss of activity after 2 min at 0.04 mM

18 entries

additional information

7 entries

competitive inhibition

658987, 674938

Anabaena sp.

reversible inhibition

bond length alterations after incubation of HydA1 with CO and H2, related to structural and oxidation state changes at the catalytic Fe atoms, e.g., to the binding of an exogenous CO at 2FeH in CO-inhibited enzyme

binds irreversibly, hydrogenase I has a lower affinity for CO than hydrogenase II

reversible inhibition

Q84GM3; Q4G6A7

reversible inhibition

binds terminally to the distal iron center

Desulfovibrio vulgaris str. Hildenborough

binds terminally to the distal iron center

Q841J7; Q84IJ8

reversible inhibition

noncompetitive vs. oxidized methyl viologen, competitive vs. H2

reversible inhibition

CO is a competitive inhibitor with respect to H2

50% inhibition at 7.5% CO in the gas phase

Q3C1T8; Q3C1T9

reversible inhibition

the bis(PMe3) nitrosyl complexes readily undergo CO substitution to give the (PMe3)3 derivatives

704161

reversible inhibition

weak, reversible, competitive

Cr3+

weak inhibition

Cr3+

weak inhibition

Cr6+

0.03 mM, complete inhibition of methyl viologen reduction

Cr6+

0.1 mM, complete inhibition of methyl viologen reduction

Cu2+

65% loss of activity after 2 min at 0.005 mM, complete inhibition at 0.1 mM in the presence of ascorbate, no inhibition observed without ascorbate

Cu2+

95% inhibition at 0.1 mM

Cu2+

complete inhibition at 1 mM

maintains 100% of its initial activity after a 48 h exposure to air, after 120 and 168 h exposures, the residual activities are 90% and 75%, respectively. It is very tolerant to oxygen

reversible inactivation; reversible inhibition

Anabaena sp.

reversible inhibition

non competitive versus methylene blue, uncompetitive versus H2, reversibility is time-dependent, inhibition is protected by H2

competitive inhibitor, irreversible inhibition

the direct interaction of the [2Fe]H subsite with dioxygen is an exothermic and specific reaction in which O2 most favorably binds in an end-on manner to the distal iron. Irreversibility of dioxygen-induced enzyme inactivation by water release and degradation of the ligand environment of the H-cluster

704015

reversible inhibition

Q84GM3; Q4G6A7

reversible inhibition

reacts with the enzyme, reversibly, causing inactivation. Although traces of O2 (less than 1%) rapidly and completely remove H2 oxidation activity, the enzyme sustains partial activity for H2 production even in the presence of 1% O2 in the atmosphere. O2 tolerance of the [NiFeSe]-hydrogenase is greater at higher temperature

Q841J7; Q84IJ8

reversible inhibition

enzyme is quite stable under air atmosphere, half-life of activity is ca. 48 h at 4Â°C, inactivation is irreversible

reversible inhibition

the enzyme is irreversibly inhibited under aerobic conditions

Q3C1T8; Q3C1T9

reversible inhibition

Persephonella hydrogeniphila

exhibits 80% residual activity after exposure to air for 24 h, decreases to 75% and 37% after 48 and 72 h exposures, respectively. After a 96 h exposure, activity is undetectable. The enzyme is oxygen sensitive

reversible

reversible inhibition

additional information

loss of Fe-Fe distances in protein purified under mildly oxidizing conditions, partial degradation of the H-cluster

additional information

is oxygen-tolerant

additional information

is oxygen-tolerant

additional information

not inhibited by CO

686732

additional information

immobilization of synthetic analogues of the [FeFe]H2ase active site on polyethyleneglycol-rich polystyrene beads

703361

additional information

isomerization of the terminal hydride is inhibited both by the basicity of the Fe2 complex as well as by the steric size of the dithiolate in the models. In the enzyme, terminal-bridge isomerization may also be inhibited by hydrogen bonding between CNdistal and a epsilon-ammonium center of a nearby, highly conserved lysine residue

704012

additional information

front velocity decreases on increase of the electron acceptor benzyl viologen concentration at all measured hydrogenase concentrations

show all columns Go to Activating Compound Search

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ACTIVATING COMPOUND

ORGANISM

UNIPROT

COMMENTARY

LITERATURE

IMAGE

3,4-dihydroxy-L-phenylalanine

substitutes for tyrosine to stimulate in vitro HydA1 activation, improves HydA1 maturation 4fold

demethylmenaquinone

HoxL

the auxiliary protein HoxL participates specifically in the maturation of the large subunit of the enzyme. It is essential for H2-oxidizing activity and enzyme-driven growth on H2. HoxL acts as a specific chaperone assisting the transfer of the Fe(CN-)2CO cofactor intermediate from the Hyp machinery to the enzyme

HoxV

the auxiliary protein HoxL participates specifically in the maturation of the large subunit of the enzyme. It is essential for H2-oxidizing activity and enzyme-driven growth on H2. HoxV functions as a scaffold delivering the Fe(CN-)2CO moiety to the precursor of the large subunit pre-HoxG of the enzyme

HydE

HydEF

maturase, role in biosynthesis of the active site. HydEF and hydG, coexpressed with the structural genes hydA1 and hydA2 in Escherichia coli lead to active [FeFe]-hydrogenase

HydF

HydG

HypB

accessory protein HypB is necessary for the production of active hydrogenase

702218

HypC

is essential for cofactor assembly

menaquinone

S-adenosyl methionine

exogenous S-adenosyl methionine stimulates in vitro hydrogenase activation, but does not individually enhance hydrogenase activation. 2 mM increases hydrogenase activity 4fold

Sulfide

1 mM increases hydrogenase activity 4fold, is not sufficient to increase hydrogenase activities without S-adenosyl methionine and the standard 20 L-amino acids

additional information

5 entries

HydE

from Clostridium acetobutylicum extracts, activation of HydADELTAEFG requires the presence of a preformed [4Fe-4S] cluster on HydA

HydE

is required to synthesize and assemble the active site utilizing Escherichia coli metabolites

HydE

can coordinate variable amounts of Fe and sulfide

HydF

from Clostridium acetobutylicum extracts, activation of HydADELTAEFG requires the presence of a preformed [4Fe-4S] cluster on HydA

HydF

is required to synthesize and assemble the active site utilizing Escherichia coli metabolites

HydF

HydG

from Clostridium acetobutylicum extracts, activation of HydADELTAEFG requires the presence of a preformed [4Fe-4S] cluster on HydA

HydG

maturase, role in biosynthesis of the active site. HydEF and hydG, coexpressed with the structural genes hydA1 and hydA2 in Escherichia coli lead to active [FeFe]-hydrogenase

HydG

is required to synthesize and assemble the active site utilizing Escherichia coli metabolites

HydG

maturase, role in biosynthesis of the active site

additional information

guanosine triphosphate does not improve hydrogenase maturation

additional information

tyrosine enhances in vitro maturation of HydA1 hydrogenase. Tyrosine has the most significant effect on overall HydA1 activities. Cysteine enhances in vitro maturation of HydA1 hydrogenase. Cysteine has the most significant effect on early HydA1 activities

additional information

activity increases up to 2.5fold during incubation at 50Â°C under H2

additional information

nitrosyl complexes reduce at potentials that are ca. 1 V milder than their carbonyl counterparts, NO+ forms diiron dithiolates that are not isostructural with the corresponding carbonyl complexes and that display enhanced Lewis acidity

704161

additional information

front velocity increases as the overall enzyme concentration (and hence the concentration of the autocatalyst form of the enzyme) is increased

Go to Disease Search

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DISEASE

TITLE OF PUBLICATION

LINK TO PUBMED

Neoplasms

Synthetic peptides inhibit adhesion of human tumor cells to extracellular matrix proteins.

11309285

Photophobia

The active site of the [FeFe]-hydrogenase from Desulfovibrio desulfuricans. I. Light sensitivity and magnetic hyperfine interactions as observed by electron paramagnetic resonance.

16323020

Photophobia

The active site of the [FeFe]-hydrogenase from Desulfovibrio desulfuricans. II. Redox properties, light sensitivity and CO-ligand exchange as observed by infrared spectroscopy.

16323019

Pyruvate Dehydrogenase Complex Deficiency Disease

Metabolic analysis of wild-type Escherichia coli and a pyruvate dehydrogenase complex (PDHC)-deficient derivative reveals the role of PDHC in the fermentative metabolism of glucose.

20667837

Starvation

Differential Expression of the Chlamydomonas [FeFe]-Hydrogenase-Encoding HYDA1 Gene Is Regulated by the COPPER RESPONSE REGULATOR1.

22669892

Trichomonas Infections

Trichomonas stableri n. sp., an agent of trichomonosis in Pacific Coast band-tailed pigeons (Patagioenas fasciata monilis).

24918075

Typhoid Fever

Use of molecular hydrogen as an energy substrate by human pathogenic bacteria.

15667272

show all columns Go to KM Value Search

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KM VALUE [mM]

SUBSTRATE

ORGANISM

UNIPROT

COMMENTARY

LITERATURE

IMAGE

0.0045 - 1.78

benzyl viologen

0.016 - 0.021

Cr6+

0.000047 - 25

17 entries

12.5

methyl viologen

pH 7.0, 30Â°C

0.01

methylenetetrahydromethanopterin

at pH 6.0 and 25Â°C

0.128

NAD+

0.001

oxidized ferredoxin

300

oxidized methionaquinone

0.055 - 0.17

oxidized methyl viologen

4 entries

0.017 - 0.025

oxidized methylene blue

0.0075

reduced ferredoxin

additional information

Km for various electron donors

0.0045

benzyl viologen

1.78

benzyl viologen

pH 7.0, 30Â°C

0.016

Cr6+

pH 7.0

0.016

Cr6+

pH 7.0

0.021

Cr6+

pH 7.0

0.000047

Streptomyces sp.

apparent value, pH and temperature not specified in the publication

711862

0.0004

at pH 5.5, 10Â°C

713401

0.001

0.001

at pH 5.5, 20Â°C

0.002

0.005

0.006

at pH 4.5, 30Â°C

0.006

at pH 5.5, 30Â°C

0.008

at pH 5.0, 30Â°C

0.01

at pH 6.5, 30Â°C

0.0113

0.015

at pH 6.0, 30Â°C

0.024

at pH 5.5, 40Â°C

0.08

with methylene blue as electron acceptor

0.41

with methyl viologen as electron acceptor

1.9

with methyl viologen as electron acceptor

0.055

oxidized methyl viologen

purified enzyme

0.055

oxidized methyl viologen

purified enzyme, at pH 8.0 and 30Â°C

0.17

oxidized methyl viologen

cell free extract

0.17

oxidized methyl viologen

cell-free extract, at pH 8.0 and 30Â°C

0.017

oxidized methylene blue

0.025

oxidized methylene blue

pH 7.0, 30Â°C

show all columns Go to Turnover Number Search

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TURNOVER NUMBER [1/s]

SUBSTRATE

ORGANISM

UNIPROT

COMMENTARY

LITERATURE

IMAGE

1500 - 9000

Abz-VAA

NiFe hydrogenase attached to a pyrolytic graphite electrode

240

benzyl viologen

pH 7.0, 30Â°C

0.09 - 1.3

Cr6+

48.3

methionaquinone

methyl viologen

pH 7.0, 30Â°C

560

methylene blue

pH 7.0, 30Â°C

additional information

turnover number for various electron donors

0.09

Cr6+

pH 7.0

0.23

Cr6+

pH 7.0

1.3

Cr6+

pH 7.0

show all columns Go to kcat/KM Value Search

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kcat/KM VALUE [1/mMs^-1]

SUBSTRATE

ORGANISM

UNIPROT

COMMENTARY

LITERATURE

IMAGE

135

benzyl viologen

pH 7.0, 30Â°C

1.6

methyl viologen

pH 7.0, 30Â°C

22400

methylene blue

pH 7.0, 30Â°C

show all columns Go to Ki Value Search

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Ki VALUE [mM]

INHIBITOR

ORGANISM

UNIPROT

COMMENTARY

LITERATURE

IMAGE

0.00016 - 0.0355

0.16 - 1.35

Ni2+

0.0025 - 0.0055

0.00016

0.007

30Â°C, pH 7.0

0.0355

0.16

Ni2+

30Â°C, pH 9.0

1.35

Ni2+

30Â°C, pH 7.0

0.0025

membrane-associated enzyme

0.0055

purified enzyme

show all columns Go to Specific Activity Search

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SPECIFIC ACTIVITY [µmol/min/mg]

ORGANISM

UNIPROT

COMMENTARY

LITERATURE

0.008

hydrogen uptake specific activity of the hydrogenase 3 lacking mutant enzyme HD705/pBS(Kan), using methyl viologen as a substrate

0.035

hydrogen uptake specific activity of the wild type enzyme, using methyl viologen as a substrate

0.0613

0.107

crude extract

0.4 - 0.7

H2 evolution

0.942

Thermoanaerobacterium saccharolyticum

1.92

methyl viologen reduction by H2

704309

10.6

1078

after 152fold purification, at 55Â°C, pH 7.0, using phenazine methosulfate as electron acceptor

110

purified enzyme

114

acceptor methyl viologen

14.6

purified enzyme, proton reduction activity

14.8

2.4fold purified enzyme, hydrogen oxidation activity

150

at pH 6.0 and 25Â°C

161

Cr6+ reduction

173 - 178

crude extract, at 55Â°C, pH 7.0, using methylene blue as electron acceptor

205

H2 uptake

230

H2 evolution

285

after 152fold purification, at 55Â°C, pH 7.0, using dichloroindophenol as electron acceptor

300

332

H2 uptake

344

after 152fold purification, at 55Â°C, pH 7.0, using methylene blue as electron acceptor

360

CO treated

484

after 152fold purification, at 80Â°C, pH 7.0, using methylene blue as electron acceptor

50000

H2 uptake

after 152fold purification, at 55Â°C, pH 7.0, using methyl viologen as electron acceptor

590

HydA1ox

620

H2 treated

624

acceptor 2,3-dimethylnaphthoquinol

650

HydA1red

7680

Cr6+ reduction

783

H2 uptake

792

H2 oxidation

H2 formation with reduced ferredoxin

additional information

300

300

acceptor benzyl viologen

reduction of ferredoxin

Persephonella hydrogeniphila

467fold purified enzyme

H2 uptake

Cr6+ reduction

additional information

specific activities with various electron donors

additional information

Klebsiella aerogenes

evaluation of hydrogenase activities in Enterobacter aerogenes with respect to H2 evolution and its uptake by using intact cells and appropriate surfactants

672729

additional information

specific activities with various electron donors

show all columns Go to pH Optimum Search

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pH OPTIMUM

ORGANISM

UNIPROT

COMMENTARY

LITERATURE

4.5

H2 production

5.5 - 6.5

the steady-state current caused by catalytic uptake of hydrogen is maximal at pH 5.5-6.5 under overvoltage of 30-60 mV

5.9

the maximum H2 oxidation current increases as the pH is raised from 4.3 to 5.9

674190

6 - 6.5

the steady-state current caused by catalytic uptake of hydrogen is maximal at pH 6.0-6.5 under overvoltage of 30-60 mV

6.5

optimal pH for the proton reduction activity

6.8

7.5

4 entries

7.8

H2 uptake

8.5

8.5 - 9.5

H2 oxidation

9.5

in solution

additional information

solubilization of the imer is associated with a downshift of the optimum pH for H2-oxidizing activity

H2 production

H2 evolution

H2 evolution

optimal catalytic activity near neutral pH

7.5

assay at

Methanococcus maripaludis

7.5

assay at

Methanothermococcus thermolithotrophicus

7.5

assay at

7.5

Methanotorris igneus

assay at

H2 oxidation

8.5

optimal pH for the hydrogen oxidation activity

8.5

8.5

50 mM Tris-HCl

show all columns Go to pH Range Search

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pH RANGE

ORGANISM

UNIPROT

COMMENTARY

LITERATURE

3.5 - 9

H2 evolution, pH 3.5 and 9.0: ca. 50% of maximal activity

4.3 - 8.4

the maximum H2 oxidation current increases as the pH is raised from 4.3 to 5.9, then it is constant up to pH 8.4

674190

5 - 10

H2 uptake is constant over a pH range from pH 5 to pH 10

5.5 - 9

H2 oxidation, pH 5.5: 40% of maximal activity, pH 9: 60% of maximal activity

6 - 11

almost no activity at pH 6.0, approx. 30% of maximal activity at pH 11.0

6 - 9

optimal pH range for the hydrogen oxidation activity is 8.5 to 9.0, optimal pH range for the proton reduction activity is 6.0 to 6.5

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TEMPERATURE OPTIMUM

ORGANISM

UNIPROT

COMMENTARY

LITERATURE

at pH 6.0, using 10 mM methyl viologen or 20 mM sodium hydrosulfite as electron acceptors

80 - 95

above

assay at

optimal temperature for the hydrogen oxidation activity and for the proton reduction activity

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TEMPERATURE RANGE

ORGANISM

UNIPROT

COMMENTARY

LITERATURE

10 - 90

at 90Â°C the enzyme retains 83% of maximum activity, at lower temperatures hydrogenase activity remains the same as at 10Â°C (13% of maximum activity), similar activity is observed between 40 and 60Â°C (about 70% of maximum activity)

20 - 95

almost no activity at 20Â°C, approx. 20% of maximal activity at 95Â°C