Information on EC 1.14.16.2 - tyrosine 3-monooxygenase and Organism(s) Homo sapiens

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The enzyme appears in selected viruses and cellular organisms

EC NUMBER
COMMENTARY hide
1.14.16.2
-
RECOMMENDED NAME
GeneOntology No.
tyrosine 3-monooxygenase
REACTION
REACTION DIAGRAM
COMMENTARY hide
ORGANISM
UNIPROT
LITERATURE
L-tyrosine + tetrahydrobiopterin + O2 = L-dopa + 4a-hydroxytetrahydrobiopterin
show the reaction diagram
REACTION TYPE
ORGANISM
UNIPROT
COMMENTARY hide
LITERATURE
oxidation
-
-
-
-
redox reaction
-
-
-
-
reduction
-
-
-
-
PATHWAY
BRENDA Link
KEGG Link
MetaCyc Link
betalamic acid biosynthesis
-
-
catecholamine biosynthesis
-
-
rosmarinic acid biosynthesis II
-
-
catecholamine biosynthesis
-
-
Tyrosine metabolism
-
-
Folate biosynthesis
-
-
Isoquinoline alkaloid biosynthesis
-
-
Metabolic pathways
-
-
SYSTEMATIC NAME
IUBMB Comments
L-tyrosine,tetrahydrobiopterin:oxygen oxidoreductase (3-hydroxylating)
The active centre contains mononuclear iron(II). The enzyme is activated by phosphorylation, catalysed by EC 2.7.11.27, [acetyl-CoA carboxylase] kinase. The 4a-hydroxytetrahydrobiopterin formed can dehydrate to 6,7-dihydrobiopterin, both spontaneously and by the action of EC 4.2.1.96, 4a-hydroxytetrahydrobiopterin dehydratase. The 6,7-dihydrobiopterin can be enzymically reduced back to tetrahydrobiopterin, by EC 1.5.1.34 (6,7-dihydropteridine reductase), or slowly rearranges into the more stable compound 7,8-dihydrobiopterin.
CAS REGISTRY NUMBER
COMMENTARY hide
9036-22-0
-
ORGANISM
COMMENTARY hide
LITERATURE
UNIPROT
SEQUENCE DB
SOURCE
GENERAL INFORMATION
ORGANISM
UNIPROT
COMMENTARY hide
LITERATURE
metabolism
SUBSTRATE
PRODUCT                       
REACTION DIAGRAM
ORGANISM
UNIPROT
COMMENTARY
(Substrate) hide
LITERATURE
(Substrate)
COMMENTARY
(Product) hide
LITERATURE
(Product)
Reversibility
r=reversible
ir=irreversible
?=not specified
3,4-dihydroxy-L-phenylalanine + 6,7-dimethyltetrahydropteridine + O2
?
show the reaction diagram
3,4-dihydroxy-L-phenylalanine + tetrahydropterin + O2
?
show the reaction diagram
L-phenylalanine + tetrahydrobiopterin + O2
L-tyrosine + 3-hydroxyphenylalanine + dihydropteridine + H2O
show the reaction diagram
-
the enzyme prefers L-tyrosine as a substrate over L-phenylalanine by an order of magnitude
-
-
?
L-phenylalanine + tetrahydropteridine + O2
3,4-dihydroxy-L-phenylalanine + dihydropteridine + H2O
show the reaction diagram
-
-
-
?
L-phenylalanine + tetrahydropteridine + O2
L-tyrosine + dihydropteridine + H2O
show the reaction diagram
-
-
-
?
L-tryptophan + tetrahydrobiopterin + O2
?
show the reaction diagram
-
the enzyme prefers L-tyrosine as a substrate over L-tryptophan by 25fold
-
-
?
L-tyrosine + (6R)-L-erythro-1',2'-dihydroxypropyltetrahydropterin + O2
?
show the reaction diagram
-
-
-
-
?
L-tyrosine + (6R)-L-erythro-tetrahydrobiopterin + O2
?
show the reaction diagram
L-tyrosine + (6RS)-L-erythro-tetrahydrobiopterin + O2
?
show the reaction diagram
-
-
-
-
?
L-tyrosine + (6S)-L-erythro-tetrahydrobiopterin + O2
?
show the reaction diagram
-
-
-
-
?
L-tyrosine + 2-methyl-4-oxo-5,6,7,8-tetrahydropterin + O2
?
show the reaction diagram
-
recombinant hTH1
-
-
?
L-tyrosine + 5,6,7,8,-tetrahydro-L-biopterin + O2
3,4-dihydroxy-L-phenylalanine + 4a-hydroxytetrahydro-L-biopterin
show the reaction diagram
-
-
-
-
?
L-tyrosine + 5,6,7,8-tetrahydro-L-biopterin + O2
3,4-dihydroxy-L-phenylalanine + 4a-hydroxytetrahydro-L-biopterin
show the reaction diagram
-
-
-
-
?
L-tyrosine + 6,7-dimethyl-2-amino-4-hydroxy-5,6,7,8-tetrahydopteridine + O2
3,4-dihydroxyphenylalanine + ?
show the reaction diagram
-
-
-
-
?
L-tyrosine + 6,7-dimethyl-2-amino-4-hydroxy-5,6,7,8-tetrahydopteridine + O2
?
show the reaction diagram
-
-
-
-
?
L-tyrosine + 6-methyltetrahydropterin + O2
?
show the reaction diagram
L-tyrosine + tetrahydrobiopterin + O2
3,4-dihydroxy-L-phenylalanine + 4a-hydroxytetrahydrobiopterin
show the reaction diagram
L-tyrosine + tetrahydrobiopterin + O2
3,4-dihydroxy-L-phenylalanine + dihydrobiopterin + H2O
show the reaction diagram
L-tyrosine + tetrahydrobiopterin + O2
3,4-dihydroxy-L-phenylalanine + dihydropteridine + H2O
show the reaction diagram
additional information
?
-
NATURAL SUBSTRATES
NATURAL PRODUCTS
REACTION DIAGRAM
ORGANISM
UNIPROT
COMMENTARY
(Substrate) hide
LITERATURE
(Substrate)
COMMENTARY
(Product) hide
LITERATURE
(Product)
REVERSIBILITY
r=reversible
ir=irreversible
?=not specified
L-tyrosine + (6R)-L-erythro-tetrahydrobiopterin + O2
?
show the reaction diagram
-
probable regulatory role of cosubstrate for all 4 isoforms
-
-
?
L-tyrosine + tetrahydrobiopterin + O2
3,4-dihydroxy-L-phenylalanine + 4a-hydroxytetrahydrobiopterin
show the reaction diagram
L-tyrosine + tetrahydrobiopterin + O2
3,4-dihydroxy-L-phenylalanine + dihydrobiopterin + H2O
show the reaction diagram
L-tyrosine + tetrahydrobiopterin + O2
3,4-dihydroxy-L-phenylalanine + dihydropteridine + H2O
show the reaction diagram
additional information
?
-
COFACTOR
ORGANISM
UNIPROT
COMMENTARY hide
LITERATURE
IMAGE
(6R)-L-erythro-5,6,7,8-tetrahydrobiopterin
-
i.e. BH4, complex regulation by the cofactor including both enzyme inactivation and conformational stabilization, competitive inhibition
5,6,7,8-tetrahydro-L-biopterin
-
-
additional information
-
a non-heme iron enzyme
-
METALS and IONS
ORGANISM
UNIPROT
COMMENTARY hide
LITERATURE
Cu2+
-
slightly activating
INHIBITORS
ORGANISM
UNIPROT
COMMENTARY hide
LITERATURE
IMAGE
(6R)-L-erythro-1',2'-dihydroxypropyltetrahydropterin
-
80% inhibition when the enzyme is preincubated with (6R)-L-erythro-1',2'-dihydroxypropyltetrahydropterin. Inhibition was attenuated by simultanious addition of dopamine
(6R)-L-erythro-5,6,7,8-tetrahydrobiopterin
-
i.e. BH4, cofactor, complex regulation by the cofactor including both enzyme inactivation and conformational stabilization, competitive inhibition, synergistically with DTT
(6S)-L-erythro-1',2'-dihydroxypropyltetrahydropterin
-
80% inhibition when the enzyme is preincubated with (6S)-L-erythro-1',2'-dihydroxypropyltetrahydropterin
1,10-phenanthroline
-
complete
2,4-diamino-6-dihydroxypropyl-5,6,7,8-tetrahydropterin
-
competitive against (6R)-L-erythro-tetrahydrobiopterin
3,4-dihydroxy-L-phenylalanine
3,4-dihydroxyphenylacetaldehyde
3-iodo-L-tyrosine
5(N-phenylthiocarbamoyl)-5,6,7,8-tetrahydropterin
-
-
5-methyl-5,6,7,8-tetrahydropterin
-
competitive against (6R)-L-erythro-tetrahydrobiopterin
6-methyltetrahydropterin
-
80% inhibition when the enzyme is preincubated with 6-methyltetrahydropterin
6-[2-(4-benzoylphenyl)propionyloxymethyl]-5,6,7,8-tetrahydropterin
-
competitive against (6R)-L-erythro-tetrahydrobiopterin
7-amino-3,3a,4,5-tetrahydro-8H-2-oxa-5,6,8,9b-tetraaza-cyclopenta[a]naphthalene-1,9-dione
-
competitive against (6R)-L-erythro-tetrahydrobiopterin
8-methyl-6,7-dimethyl-5,6,7,8-tetrahydropterin
-
competitive against (6R)-L-erythro-tetrahydrobiopterin
adrenaline
-
-
alpha-methyl-p-tyrosine
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complete inhibition at 0.001 mM
Bathocuproine sulfonate
-
slightly
bathophenanthroline sulfonate
-
-
Catecholamines
CoCl2
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0.1 mM CoCl2 results in more than 80% inhibition
dihydrobiopterin
-
L-dopa-oxidase activity
dopamine
DTT
-
inactivates the enzyme, synergistically with tetrahydrobiopterin
L-Dopa
-
above 0.15 mM inhibiting L-dopa-oxidase activity in presence of tetrahydropterin, but not with 6,7-dimethyltetrahydropterin
L-erythro-7,8-dihydrobiopterin
-
competitive against tetrahydropterin
L-phenylalanine
-
-
L-tyrosine
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-
Mn2+
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50% inhibition at 0.01 mM
N-methyl-norsalsolinol
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noncompetitive with respect to L-tyrosine, N-methyl-norsalsolinol and related tetrahydroisoquinolines accumulate in the nigrostriatal system of the human brain and are increased in the cerebrospinal fluid of patients with Parkinson’s disease
N-methyl-salsolinol
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-
Ni2+
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competitive against Fe2+
noradrenaline
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-
norsalsolinol
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N-methyl-norsalsolinol and related tetrahydroisoquinolines accumulate in the nigrostriatal system of the human brain and are increased in the cerebrospinal fluid of patients with Parkinson’s disease
tyrosine
-
substrate inhibition, with (6R)-L-erythro-tetrahydrobiopterin
Zn2+
-
competitive against Fe2+
additional information
-
ACTIVATING COMPOUND
ORGANISM
UNIPROT
COMMENTARY hide
LITERATURE
IMAGE
forskolin
-
forskolin selectively increases the phosphorylation of tyrosine hydroxylase at Ser40 by 1.8fold without increasing total tyrosine hydroxylase protein levels
thiols
-
activate the L-dopa activity
additional information
-
KM VALUE [mM]
SUBSTRATE
ORGANISM
UNIPROT
COMMENTARY hide
LITERATURE
IMAGE
0.045
6,7-dimethyl-2-amino-4-hydroxy-5,6,7,8-tetrahydopteridine
-
0.1 mM L-tyrosine, 0.1 mg/ml catalase, 50 mM HEPES pH 7.0, 0.01 mM ferrous ammonium sulfate, 1 mM dithiothreitol, 25°C
0.06 - 0.1
6-Methyl-5,6,7,8-tetrahydropterin
-
-
0.056 - 0.146
L-Dopa
0.0081 - 0.08
L-tyrosine
0.085
phenylalanine
-
-
0.0056 - 0.507
tetrahydrobiopterin
0.01
Tetrahydropterin
-
recombinant phosphorylated hTH1, L-dopa-oxidase activity
0.011 - 0.166
tyrosine
additional information
additional information
-
TURNOVER NUMBER [1/s]
SUBSTRATE
ORGANISM
UNIPROT
COMMENTARY hide
LITERATURE
IMAGE
0.8 - 5.35
L-tyrosine
0.017 - 0.58
tetrahydrobiopterin
kcat/KM VALUE [1/mMs-1]
SUBSTRATE
ORGANISM
UNIPROT
COMMENTARY hide
LITERATURE
IMAGE
1.7 - 89.3
tetrahydrobiopterin
Ki VALUE [mM]
INHIBITOR
ORGANISM
UNIPROT
COMMENTARY hide
LITERATURE
IMAGE
0.07
(6R)-L-erythro-5,6,7,8-tetrahydrobiopterin
-
pH 7.0, 25°C, versus (6R)-L-erythro-5,6,7,8-tetrahydrobiopterin
0.016
2,4-diamino-6-dihydroxypropyl-5,6,7,8-tetrahydropterin
-
-
2.83
5(N-phenylthiocarbamoyl)-5,6,7,8-tetrahydropterin
-
-
0.063
5-methyl-5,6,7,8-tetrahydropterin
-
-
0.001
6-[2-(4-benzoylphenyl)propionyloxymethyl]-5,6,7,8-tetrahydropterin
-
-
0.138
7-amino-3,3a,4,5-tetrahydro-8H-2-oxa-5,6,8,9b-tetraaza-cyclopenta[a]naphthalene-1,9-dione
-
-
0.617
8-methyl-6,7-dimethyl-5,6,7,8-tetrahydropterin
-
-
0.07
L-erythro-7,8-dihydrobiopterin
-
-
0.103
L-phenylalanine
-
0-0.4 mM L-tyrosine, 0-0.2 mM L-phenylalanine, 1 mM 6,7-dimethyl-2-amino-4-hydroxy-5,6,7,8-tetrahydopteridine, 200 mM Na-HEPES pH 7.0, 100 mM 2-mercaptoethanol, 0.2 mg/ml catalase, 37°C
0.037 - 0.073
L-tyrosine
IC50 VALUE [mM]
INHIBITOR
ORGANISM
UNIPROT
COMMENTARY hide
LITERATURE
IMAGE
0.0022
3,4-dihydroxy-L-phenylalanine
Homo sapiens
-
at pH 7.0 and 25°C
0.05
3-iodo-L-tyrosine
Homo sapiens
-
pH and temperature not specified in the publication
0.0002 - 0.0136
dopamine
0.0003
N-methyl-norsalsolinol
Homo sapiens
-
-
0.004
N-methyl-salsolinol
Homo sapiens
-
-
0.01
norsalsolinol
Homo sapiens
-
-
SPECIFIC ACTIVITY [µmol/min/mg]
ORGANISM
UNIPROT
COMMENTARY hide
LITERATURE
0.0054
-
crude enzyme, at pH 6.8 and 37°C
0.0163
-
purified enzyme, at pH 6.8 and 37°C
0.0447
-
activity in melanosomes
0.16
-
purified recombinant isoform hTH3
0.2
-
purified recombinant isoform hTH4
0.29
-
purified recombinant isoform hTH2
0.33
-
purified recombinant isoform hTH1, tyrosine concentration is 0.2 mM
0.555
-
with 0.05 mM L-tyrosine, at pH 7.0 and 25°C
0.79
-
purified recombinant isoform hTH1, tyrosine concentration is 0.05 mM
1
-
about, purified recombinant enzyme
additional information
pH OPTIMUM
ORGANISM
UNIPROT
COMMENTARY hide
LITERATURE
6 - 7
-
4 isoforms
pH RANGE
ORGANISM
UNIPROT
COMMENTARY hide
LITERATURE
5 - 8.5
-
4 isoforms
TEMPERATURE OPTIMUM
ORGANISM
UNIPROT
COMMENTARY hide
LITERATURE
30
-
assay at, crude brain enzyme extract
SOURCE TISSUE
ORGANISM
UNIPROT
COMMENTARY hide
LITERATURE
SOURCE
-
undifferentiated, hydroxylase isoenzyme I mRNA, no detection of isoenzyme 2, 3 and 4
Manually annotated by BRENDA team
-
increased enzyme contents in violent suicidal depressive patients, analysis of postmortem brains of control individuals, non-suicidal depressive patients, and non-violent and violent suicidal depressive patients
Manually annotated by BRENDA team
-
epidermal, hydroxylase isoenzyme I mRNA, no detection of isoenzyme 2, 3 and 4
Manually annotated by BRENDA team
-
37 different tumor samples, analysis of enzyme expression
Manually annotated by BRENDA team
-
a dopaminergic-like, neuroblastoma cell line
Manually annotated by BRENDA team
-
a dopaminergic cell line
Manually annotated by BRENDA team
-
the superior cervical ganglion of the sympathetic nervous system is filled with many neuronal somata and fibers with strong immunoreactivity for tyrosine hydroxylase, TH-positive fibers are not evenly distributed within the nerve bundles of the ganglia, but tend to be located at their circumference
Manually annotated by BRENDA team
LOCALIZATION
ORGANISM
UNIPROT
COMMENTARY hide
GeneOntology No.
LITERATURE
SOURCE
-
mutant enzymes T283M and R306H expressed in Escherichia coli are mainly found in inclusion bodies but a small amount of soluble enzyme is produced
Manually annotated by BRENDA team
-
mutant enzyme T245P and T463 M expressed in Escherichia coli are predominantly soluble. Mutant enzymes T283M and R306H expressed in Escherichia coli are mainly found in inclusion bodies but a small amount of soluble enzyme is produced
-
Manually annotated by BRENDA team
MOLECULAR WEIGHT
ORGANISM
UNIPROT
COMMENTARY hide
LITERATURE
24000
-
4 isoforms, gel filtration
56000
-
x * 56000, SDS-PAGE
58000
-
x * 58000, recombinant enzyme, SDS-PAGE
60000
-
4 * 60000, 4 isoforms, SDS-PAGE
70000
-
4 * 70000, SDS-PAGE
98900
-
recombinant enzyme, SDS-PAGE
300000
-
gel filtration
SUBUNITS
ORGANISM
UNIPROT
COMMENTARY hide
LITERATURE
homotetramer
-
4 * 70000, SDS-PAGE
tetramer
-
4 * 60000, 4 isoforms, SDS-PAGE
POSTTRANSLATIONAL MODIFICATION
ORGANISM
UNIPROT
COMMENTARY hide
LITERATURE
phosphoprotein
Crystallization/COMMENTARY
ORGANISM
UNIPROT
LITERATURE
complex of 14-3-3gamma protein and phosphorylated tyrosine hydroxylase(1-43), sitting drop vapor diffusion method, using 30% (w/v) polyethylene glycol 2000 monomethyl ether as precipitant
-
crystal structure, analysis of tetrahydropterin analogues binding to isoform hTH1
-
pH STABILITY
ORGANISM
UNIPROT
COMMENTARY hide
LITERATURE
7
-
preincubation at 37°C for 2 h above, isoforms are stable; preincubation at 37°C for 2 h below, enzyme isoforms are unstable, especially isoforms hTH1 and hTH3
438705
8
-
isoforms, optimal stability at
438705
TEMPERATURE STABILITY
ORGANISM
UNIPROT
COMMENTARY hide
LITERATURE
37
-
5 h, stable, catecholamine, N-methyl-norsalsolinol, or norsalsolinol binding increases the thermal stability of tyrosine hydroxylase
41
-
Tm-value of mutant enzyme T463M is 44.3°C
44
-
Tm-value of mutant enzyme T245P is 44.3°C
46
-
Tm-value of mutant enzyme R306H is 45.8°C
48
-
Tm-value of wild-type enzyme is 48.2°C
50
-
50% loss of activity after 90 min, 80% loss of activity after 2 h, wild-type enzyme
additional information
-
thermal stability of hTH1 is increased by phosphorylation at Ser-40
GENERAL STABILITY
ORGANISM
UNIPROT
LITERATURE
binding of inhibitor dopamine and of cofactor tetrahydrobioterin stabilizes the enzyme
-
catecholamine binding improves tyrosine hydroxylase's resistance to proteolysis
-
the 14-3-3eta protein regulates tyrosine hydroxylase type 1 stability against degradation by acting on the N-terminus
-
STORAGE STABILITY
ORGANISM
UNIPROT
LITERATURE
-80°C, purified wild-type enzyme can be stored indefinetely in absence of glycerol. the mutant enzymes T245P and T463M behave similarly. The removal of glyceryl from the T283M and R306H enzymes results in significant precipitation and loss of the protein
-
Purification/COMMENTARY
ORGANISM
UNIPROT
LITERATURE
4 isoforms, recombinant from Escherichia coli
-
amylose resin column chromatography and HiPrep Q column chromatography
-
GST-Sepharose column chromatography
-
heparin Sepharose chromatography
-
Hi-TRAP heparin column
-
more than 90% homogeneity
-
Ni-chelating Sepharose fast flow bead chromatography
-
one chromatography step
-
Cloned/COMMENTARY
ORGANISM
UNIPROT
LITERATURE
4 isoforms, overexpression in Escherichia coli, phosphorylation-free
-
DNA and amino acid sequence determination and analysis of wild-type enzyme and polymorphic genetic variants, expression in human chromaffin cells
-
enzyme expression by in vitro transcription-translation using a rapid translation system with enhanced Escherichia coli lysate and radio-labeled L-Met, tetrahydrobioterin increases the enzyme protein yield
-
expressed in Escherichia coli BL21(DE3)
-
expressed in Escherichia coli BL21(DE3) cells
-
expressed in Escherichia coli BL21(DE3) pLysS cells
-
expressed in monkey striatum using harmless adeno-associated virus vectors and in PC-12 cells and AtT-20 cells
-
expressed in SH-SY5Y cells
-
expressed in SH-SY5Y, SK-N-BE(2), and IMR-32 cells
GQ403014 and GQ403013 and GQ403012
expression in Escherichia coli
-
expression in Escherichia coli BL21(DE3)
-
expression in Escherichia coli BL21(DE3) as maltose-binding protein fusion protein
-
expression of gene fragment, comprising positions -495 to +25, which have regulatory promoter function, from a pGL-Basic luciferase reporter vector in MES23.5 cells and MES23.5 alpha-synuclein-overexpressing cells, alpha-synuclein is a negative regulator of the tyrosine hydroxylase expression via trans-acting function on the TH promoter, overview
-
isoform 1 hTH1 and His-tagged truncated mutant, expression in Escherichia coli
-
isozyme DNA and amino acid sequence determination and analysis, RT-PCR analysis of isozyme expression in neuroblastoma tumors, in abdominal and thoracic tumours and foetal adrenal glands, using external and internal primers, 4.0fold lower expression level in adrenal glands than in abdominal tumors, overview, expression of the enzyme mutant lacking exons 2, 8, and 9 in HeLa cells
-
EXPRESSION
ORGANISM
UNIPROT
LITERATURE
striatal tyrosine hydroxylase shows a 49.8% reduction compared to control values in incidental Lewy body disease cases
-
ENGINEERING
ORGANISM
UNIPROT
COMMENTARY hide
LITERATURE
D361N
-
reductions in Vmax are not significantly different from the wild type enzyme
E332A
-
the mutant has 10fold higher Km for 6-methyltetrahydropterin, but reduction of the enzyme by 6-methyltetrahydropterin is similar to the wild type
E332D
-
active site residue, 10fold reduction in activity, close to the catalytic iron
E332Q
-
active site residue, no activity, close to the catalytic iron
E362G
-
the Vmax is reduced compared to the wild type enzyme
E362Q
-
reductions in Vmax are not significantly different from the wild type enzyme
E362R/E365R
-
the Vmax is significantly less reduced by dopamine than for the wild type enzyme
E365G
-
the Vmax is reduced compared to the wild type enzyme
E365Q
-
the Vmax is significantly less reduced by dopamine than for the wild type enzyme
F184W/W372F
-
4fold lower Km for L-tyrosine compared to the wild-type enzyme. Similar Km for 6,7-dimethyl-2-amino-4-hydroxy-5,6,7,8-tetrahydopteridine compared to wild-type enzyme
F300A
-
active site residue
F300Y
-
active site residue
K170E/L480A
-
the mutant is inhibited over the same range of dopamine like the wild type enzyme
K366L
-
reductions in Vmax are not significantly different from the wild type enzyme
L205P
-
the mutant is associated with recessively inherited L-DOPA-responsive infantile parkinsonism, the mutation reduces the activity and stability of the protein in cells and in vitro expression systems, being considered a misfolding mutation
L294A
-
protrudes into catalytic cleft
L294Y
-
protrudes into catalytic cleft
R306H
-
1.2fold decrease in Km-value for L-tyrosine compared to wild-type enzyme, Ki-value for L-tyrosine is nearly identical to wild-type value, 1.3fold decrease in KM-value for tetrahydrobiopterin compared to wild-type enzyme, 1.2fold increase of turnover-number compared to wild-type enzyme. 8.2°C increase in Tm-value compared to wild-type enzyme
R306H/T463M
-
all of the TyrH is insoluble and no enzyme can be purified
R37E/R38E
S368A
-
the Vmax is significantly less reduced by dopamine than for the wild type enzyme
S40E
-
the mutant mimics a phosphorylation of S40. The kinetics of reduction and oxidation of the enzyme are similar to the wild type
T245P
-
1.4fold increase in Km-value for L-tyrosine compared to wild-type enzyme, 1.6fold increase in Ki-value for L-tyrosine compared to wild-type enzyme, 1.1fold increase in KM-value for tetrahydrobiopterin compared to wild-type enzyme, 1.6fold increase of turnover-number compared to wild-type enzyme. 3.9°C increase in Tm-value compared to wild-type enzyme
T245P/T283M
-
all of the TyrH is insoluble and no enzyme can be purified
T283M
-
1.2fold decrease in Km-value for L-tyrosine compared to wild-type enzyme, 1.2fold decrease in Ki-value for L-tyrosine compared to wild-type enzyme, 1.3fold decrease in KM-value for tetrahydrobiopterin compared to wild-type enzyme, 4.2fold decrease of turnover-number compared to wild-type enzyme
T463M
-
1.1fold decrease in Km-value for L-tyrosine compared to wild-type enzyme, Ki-value for L-tyrosine is nearly identical to wild-type value compared to wild-type enzyme, 1.4fold decrease in KM-value for tetrahydrobiopterin compared to wild-type enzyme, 1.2fold increase of turnover-number compared to wild-type enzyme. 7.7°C increase in Tm-value compared to wild-type enzyme
W166F/F184W/W233F/W372F
-
mutant protein contains one tryptophan at residue 184 in the middle of a mobile active-site loop. The mutant was generated to perform steady-state fluorescence anisotropy measurements and shows kinetic properties similar to the wild-type enzyme
W166F/F184W/W372F
-
Km for L-tyrosine similar to the wild-type enzyme. 3fold higher Km for 6,7-dimethyl-2-amino-4-hydroxy-5,6,7,8-tetrahydopteridine compared to wild-type enzyme
W166F/W233F/W372F
-
Km for L-tyrosine similar to the wild-type enzyme. 4fold higher Km for 6,7-dimethyl-2-amino-4-hydroxy-5,6,7,8-tetrahydopteridine compared to wild-type enzyme
W166F/W372F
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Km for L-tyrosine similar to the wild-type enzyme. 3fold higher Km for 6,7-dimethyl-2-amino-4-hydroxy-5,6,7,8-tetrahydopteridine compared to wild-type enzyme
W372F
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10fold lower Km for L-tyrosine compared to the wild-type enzyme. Similar Km for 6,7-dimethyl-2-amino-4-hydroxy-5,6,7,8-tetrahydopteridine compared to wild-type enzyme
Y371F
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active site residue, close to the catalytic iron
additional information