Information on EC 3.2.1.98 - glucan 1,4-alpha-maltohexaosidase

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The enzyme appears in viruses and cellular organisms

EC NUMBER
COMMENTARY hide
3.2.1.98
-
RECOMMENDED NAME
GeneOntology No.
glucan 1,4-alpha-maltohexaosidase
REACTION
REACTION DIAGRAM
COMMENTARY hide
ORGANISM
UNIPROT
LITERATURE
Hydrolysis of (1->4)-alpha-D-glucosidic linkages in amylaceous polysaccharides, to remove successive maltohexaose residues from the non-reducing chain ends
show the reaction diagram
REACTION TYPE
ORGANISM
UNIPROT
COMMENTARY hide
LITERATURE
hydrolysis of O-glycosyl bond
-
-
-
-
SYSTEMATIC NAME
IUBMB Comments
4-alpha-D-glucan maltohexaohydrolase
cf. EC 3.2.1.3 glucan 1,4-alpha-glucosidase, which removes successive glucose residues; EC 3.2.1.2 beta-amylase, which removes successive maltose residues; EC 3.2.1.116 glucan 1,4-alpha-maltotriohydrolase, which removes successive maltotriose units and EC 3.2.1.60 glucan 1,4-alpha-maltotetraohydrolase, which removes successive maltotetraose residues. The products have the alpha-configuration.
CAS REGISTRY NUMBER
COMMENTARY hide
72561-12-7
-
ORGANISM
COMMENTARY hide
LITERATURE
UNIPROT
SEQUENCE DB
SOURCE
strain 707
Uniprot
Manually annotated by BRENDA team
strain US116
-
-
Manually annotated by BRENDA team
strain US116
-
-
Manually annotated by BRENDA team
-
-
-
Manually annotated by BRENDA team
SUBSTRATE
PRODUCT                       
REACTION DIAGRAM
ORGANISM
UNIPROT
COMMENTARY
(Substrate) hide
LITERATURE
(Substrate)
COMMENTARY
(Product) hide
LITERATURE
(Product)
Reversibility
r=reversible
ir=irreversible
?=not specified
amylopectin + H2O
maltohexaose + ?
show the reaction diagram
amylopectin beta-amylase limit dextrin + H2O
oligosaccharide
show the reaction diagram
amylose + H2O
maltohexaose
show the reaction diagram
amylose + H2O
maltohexaose + maltoheptaose
show the reaction diagram
amylose + H2O
maltohexaose + maltotriose + maltoheptaose
show the reaction diagram
-
-
-
?
glycogen + H2O
maltohexaose
show the reaction diagram
glycogen beta-amylase limit dextrin + H2O
oligosaccharide
show the reaction diagram
maltoheptaose + H2O
maltohexaose + maltotriose + maltotetraose + maltopentaose + maltose + D-glucose
show the reaction diagram
-
-
-
?
maltoheptaose + p-nitrophenyl alpha-glucoside
p-nitrophenyl alpha-maltoheptaoside + D-glucose
show the reaction diagram
-
transglycosylation, mechanism
p-nitrophenyl alpha-maltoheptaoside useful substrate for assay of human alpha-amylase in serum and urine
?
maltohexaose + H2O
D-glucose + maltopentaose
show the reaction diagram
maltohexaose + H2O
maltose + maltotetraose
show the reaction diagram
maltohexaose + H2O
maltotriose
show the reaction diagram
maltononaose + H2O
maltohexaose + maltotriose
show the reaction diagram
maltooligosaccharide + H2O
maltohexaose
show the reaction diagram
maltooligosaccharide + H2O
maltooligosaccharide
show the reaction diagram
-
6 glucose units and shorter
with less than 6 glucose units
?
maltopentaose + H2O
?
show the reaction diagram
-
-
-
-
?
maltotetraose
maltohexaose + maltose
show the reaction diagram
maltotetraose + H2O
?
show the reaction diagram
-
-
-
-
?
maltotriose + H2O
?
show the reaction diagram
-
-
-
-
?
soluble starch + H2O
maltose + ?
show the reaction diagram
-
-
-
-
?
starch + H2O
maltohexaose
show the reaction diagram
starch + H2O
maltohexaose + ?
show the reaction diagram
starch + H2O
maltohexaose + maltopentaose
show the reaction diagram
starch + H2O
maltohexaose + maltotetrose + maltotriose + maltose
show the reaction diagram
-
-
the predominant products are maltohexaose (48%) followed by maltotetrose, maltotriose and maltose
-
?
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
maltohexaose + H2O
maltose + maltotetraose
show the reaction diagram
-
-
-
-
?
maltopentaose + H2O
?
show the reaction diagram
-
-
-
-
?
maltotetraose + H2O
?
show the reaction diagram
-
-
-
-
?
maltotriose + H2O
?
show the reaction diagram
-
-
-
-
?
soluble starch + H2O
maltose + ?
show the reaction diagram
-
-
-
-
?
starch + H2O
maltohexaose + maltotetrose + maltotriose + maltose
show the reaction diagram
-
-
the predominant products are maltohexaose (48%) followed by maltotetrose, maltotriose and maltose
-
?
additional information
?
-
-
the enzyme cannot hydrolyze maltose, alpha-cyclodextrin, beta-cyclodextrin, or pullulan
-
-
-
METALS and IONS
ORGANISM
UNIPROT
COMMENTARY hide
LITERATURE
CaCl2
-
extracellular enzyme, slight activation
Co2+
-
extracellular enzyme, slight activation
MgSO4
-
G-6, slight activation
MnSO4
-
extracellular enzyme, slight activation
NiCl2
-
immobilized enzyme, slight activation
Zn2+
-
immobilized enzyme, very slight activation
additional information
-
native enzyme compared with immobilized enzyme
INHIBITORS
ORGANISM
UNIPROT
COMMENTARY hide
LITERATURE
IMAGE
1-propanol
-
transglycosylation, inactivation
Ag+
-
extracellular enzyme, strong inhibition
AgNO3
Al2(SO4)3
-
immobilized enzyme, slight inactivation
BaCl2
-
G-6, slight inactivation
CoCl2
-
G-6, strong inhibition
CuSO4
EDTA
-
approximately 50% loss of activity in the presence of 2 mM EDTA
Fe2+
-
G-6, strong inhibition
FeCl3
-
immobilized enzyme
FeSO4
HgCl2
iodoacetamide
Mn2+
-
native enzyme, slight inactivation
MnCl2
-
G-6, slight inactivation
p-chloromercuribenzoate
Sn2+
-
slight inactivation
SrCl2
ZnSO4
additional information
-
native enzyme compared with immobilized enzyme
-
ACTIVATING COMPOUND
ORGANISM
UNIPROT
COMMENTARY hide
LITERATURE
IMAGE
2-mercaptoethanol
-
-
cysteine
-
very slight activation
ethanol
-
transglycosylation, activation
L-cysteine
-
-
methanol
-
aqueous methanol system, up to 40% methanol, increases transglycosylation
KM VALUE [mM]
SUBSTRATE
ORGANISM
UNIPROT
COMMENTARY hide
LITERATURE
IMAGE
7.68
maltohexaose
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-
0.36
maltononaose
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pH and temperature not specified in the publication
10.02
maltopentaose
-
-
50
maltotetraose
-
-
0.46
short-chain amylose
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-
-
additional information
additional information
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TURNOVER NUMBER [1/s]
SUBSTRATE
ORGANISM
UNIPROT
COMMENTARY hide
LITERATURE
IMAGE
12.86
maltononaose
Bacillus licheniformis
-
pH and temperature not specified in the publication
kcat/KM VALUE [1/mMs-1]
SUBSTRATE
ORGANISM
UNIPROT
COMMENTARY hide
LITERATURE
IMAGE
35.72
maltononaose
Bacillus licheniformis
-
pH and temperature not specified in the publication
5991
SPECIFIC ACTIVITY [µmol/min/mg]
ORGANISM
UNIPROT
COMMENTARY hide
LITERATURE
0.7
starch, culture medium, pH 7.6
1.5
starch, purified enzyme, pH 7.6
8.2
-
cell-bound enzyme
18.4
-
extracellular enzyme
18.8
starch, purified enzyme, pH 8.8
116
-
H-I-2
124
-
H-II
147
-
H-I-1
845
-
mutant AmyUS100DELTAIG/M197A
additional information
-
G-6
pH OPTIMUM
ORGANISM
UNIPROT
COMMENTARY hide
LITERATURE
6.8
-
cell-bound enzyme
10.5
-
-
additional information
-
native enzyme compared with immobilized enzyme, immobilized enzyme: optimum pH shifted slightly to acidic side
pH RANGE
ORGANISM
UNIPROT
COMMENTARY hide
LITERATURE
3 - 9
-
pH 3.0: 20% of maximum activity, pH 9.0: more than 60% of maximum activity
4.7 - 10.8
-
5 - 10
5 - 8
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immobilized enzyme, more than 80% of maximum activity between 5.0 and 8.0
5 - 9
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transglycosylation
5.5 - 8
-
more than 80% of maximum activity at 5.5 and 8.0
6 - 8
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extracellular enzyme, more than 80% of maximum activity between pH 6.0 and 8.0
6.6 - 8.6
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the enzyme shows at least 80% activity in the pH range of 6.6-8.6
additional information
-
native enzyme compared with immobilized enzyme
TEMPERATURE OPTIMUM
ORGANISM
UNIPROT
COMMENTARY hide
LITERATURE
35
-
transglycosylation
50
-
cell-bound enzyme
additional information
-
native enzyme compared with immobilized enzyme
TEMPERATURE RANGE
ORGANISM
UNIPROT
COMMENTARY hide
LITERATURE
20 - 80
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20C: about 30% of maximum activity, 80C: more than 20% of maximum activity
40 - 50
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-
45 - 70
activity decreases to less than 20% above 55C
45
-
transglycosylation, below, considerable inactivation at
additional information
-
native enzyme compared with immobilized enzyme
pI VALUE
ORGANISM
UNIPROT
COMMENTARY hide
LITERATURE
6.3
-
isoelectric focusing
LOCALIZATION
ORGANISM
UNIPROT
COMMENTARY hide
GeneOntology No.
LITERATURE
SOURCE
MOLECULAR WEIGHT
ORGANISM
UNIPROT
COMMENTARY hide
LITERATURE
36300
-
1 * 36920 + 1 * 36300 , estimated from native PAGE
36920
-
1 * 36920 + 1 * 36300 , estimated from native PAGE
48000
-
cell-bound and extracellular enzyme, gel filtration
54000
-
gel filtration
59000
-
H-I-2, SDS-PAGE
60000
-
SDS-PAGE
65000
-
extracellular enzyme, SDS-PAGE
73000
-
H-I-1, SDS-PAGE
75921
-
x * 75921, calculation from nucleotide sequence
76000
-
G-6, gel filtration
80000
-
H-II, SDS-PAGE
100000
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molecular weight of largest G6-amylase produced in E. coli HB101, SDS-PAGE; multiple forms G6-amylase having molecular masses: 100000, 90000, 80000, 73000, and 60000, due to intracellular proteolysis of the enzyme
102600
-
mature G6-amylase, before proteolytic processing at the COOH-terminal side of enzyme, calculated from nucleotide sequence
additional information
-
multiple forms G6-amylase having molecular masses: 100000, 90000, 80000, 73000, and 60000, due to intracellular proteolysis of the enzyme
SUBUNITS
ORGANISM
UNIPROT
COMMENTARY hide
LITERATURE
?
-
x * 75921, calculation from nucleotide sequence
heterodimer
-
1 * 36920 + 1 * 36300 , estimated from native PAGE
monomer
Crystallization/COMMENTARY
ORGANISM
UNIPROT
LITERATURE
hanging drop vapor diffusion method
hanging-drop vapor diffusion method
microbatch technique with 80 mM sodium/potassium phosphate pH 6.2 buffer containing 8% polyethylene glycol 3350 and 40 mM sodium thiocyanate at 20C
-
pH STABILITY
ORGANISM
UNIPROT
COMMENTARY hide
LITERATURE
4 - 11
-
immobilized enzyme, stable between
171735
4
-
transglycosylation, complete inactivation
171731
4.7 - 10.8
retaining more than 50% of starch-degrading activity at 37C
664017
5 - 10
6 - 9
-
cell-bound enzyme: 20% loss of activity, 60 min, 40C
171734, 171738, 171739
10
-
50% loss of activity
171734
11
-
extracellular enzyme, most of activity lost above pH 11.0
171738
11.5
-
immobilized enzyme, 85% of activity retained
171735
additional information
TEMPERATURE STABILITY
ORGANISM
UNIPROT
COMMENTARY hide
LITERATURE
20 - 45
-
cell-bound enzyme, stable between, 1 h
40
-
completely stable up to, with Ca2+
45
-
transglycosylation, considerabe inactivation
60
-
all activity lost after 15 min
65 - 70
-
5-3h half-life of the enzyme
75
-
immobilized enzyme, 15 min at 75C: 40% of activity retained
100
-
mutant protein AmyUS100-IG missing Ile214-Gly215 residues, 70 min stable in presence of 25 mM CaCl2; wild-type Bacillus Amy, 15 min stable in presence of 100 mM CaCl2
additional information
GENERAL STABILITY
ORGANISM
UNIPROT
LITERATURE
Ca2+ stabilizes, enzyme is more thermostable in the presence of Ca2+
-
immobilized enzyme is very stable
-
immobilized enzyme stable to repeated use of 20 cycles
-
substrate has protective effect on enzyme stability
-
ORGANIC SOLVENT
ORGANISM
UNIPROT
COMMENTARY hide
LITERATURE
Ethanol
-
stable and activation
Methanol
-
stable up to 40%, at 50% methanol: inactivation of transglycosylation and hydrolysis
Purification/COMMENTARY
ORGANISM
UNIPROT
LITERATURE
acetone precipitation, gel filtration, ion-exchange chromatography
-
affinity chromatography using the IMPACT-CN system
-
by affinity purification
-
DE-52 column chromatography, Sepharose FF column chromatography and Highload Superdex 200 column chromatography
-
DEAE-Sepharose column chromatography
gel filtration
Ni-NTA resin column chromatography
-
Cloned/COMMENTARY
ORGANISM
UNIPROT
LITERATURE
expressed and multiform G6-amylase produced in Escherichia coli HB101
-
expressed in Bacillus subtilis strain 207-25
expressed in Escherichia coli
-
expressed in Escherichia coli strain B834(DE3)
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expressed in Escherichia coli strain MC1061
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Wild-type G6-amylase for use in crystallographic analysis produced by the transformants of Bacillus subtilis 207-25, wild-type and mutant G6-amylases for use in activity measurement were produced in a protease-deficient mutant Escherichia coli ME8417
EXPRESSION
ORGANISM
UNIPROT
LITERATURE
soluble starch as well as raw starch induce the enzyme expression, induction being higher with raw starch
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ENGINEERING
ORGANISM
UNIPROT
COMMENTARY hide
LITERATURE
additional information
APPLICATION
ORGANISM
UNIPROT
COMMENTARY hide
LITERATURE
food industry
industry
synthesis