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Synonyms
beta-amylase, arath, spoii, beta amylase, tr-bamy, ct-bmy, bam-2, beta-amylase 1, glycogenase, bam-8,
more
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(alpha-D-glucopyranosyl-(1-4))n-alpha-D-glucopyranose + H2O = (alpha-D-glucopyranosyl-(1-4))n-2-alpha-D-glucopyranose + alpha-D-glucopyranosyl-(1-4)-beta-D-glucopyranose
(alpha-D-glucopyranosyl-(1-4))n-alpha-D-glucopyranose + H2O = (alpha-D-glucopyranosyl-(1-4))n-2-alpha-D-glucopyranose + alpha-D-glucopyranosyl-(1-4)-beta-D-glucopyranose

mechanism
(alpha-D-glucopyranosyl-(1-4))n-alpha-D-glucopyranose + H2O = (alpha-D-glucopyranosyl-(1-4))n-2-alpha-D-glucopyranose + alpha-D-glucopyranosyl-(1-4)-beta-D-glucopyranose
multichain type mechanism
-
(alpha-D-glucopyranosyl-(1-4))n-alpha-D-glucopyranose + H2O = (alpha-D-glucopyranosyl-(1-4))n-2-alpha-D-glucopyranose + alpha-D-glucopyranosyl-(1-4)-beta-D-glucopyranose
catalytic mechanism
-
(alpha-D-glucopyranosyl-(1-4))n-alpha-D-glucopyranose + H2O = (alpha-D-glucopyranosyl-(1-4))n-2-alpha-D-glucopyranose + alpha-D-glucopyranosyl-(1-4)-beta-D-glucopyranose
catalytic mechanism
(alpha-D-glucopyranosyl-(1-4))n-alpha-D-glucopyranose + H2O = (alpha-D-glucopyranosyl-(1-4))n-2-alpha-D-glucopyranose + alpha-D-glucopyranosyl-(1-4)-beta-D-glucopyranose
acts on starch, glycogen and related polysaccharides and oligosaccharides producing beta-maltose by an inversion, the term beta relates to the initial anomeric configuration of the free sugar group released and not to the configuration of the linkage hydrolysed
-
(alpha-D-glucopyranosyl-(1-4))n-alpha-D-glucopyranose + H2O = (alpha-D-glucopyranosyl-(1-4))n-2-alpha-D-glucopyranose + alpha-D-glucopyranosyl-(1-4)-beta-D-glucopyranose
catalytic mechanism, reaction mechanism
-
(alpha-D-glucopyranosyl-(1-4))n-alpha-D-glucopyranose + H2O = (alpha-D-glucopyranosyl-(1-4))n-2-alpha-D-glucopyranose + alpha-D-glucopyranosyl-(1-4)-beta-D-glucopyranose
active site structure, carbohydrate binding subsites, role of a conformational change of the inner loop in the catalytic mechanism, T342 is involved, overview
(alpha-D-glucopyranosyl-(1-4))n-alpha-D-glucopyranose + H2O = (alpha-D-glucopyranosyl-(1-4))n-2-alpha-D-glucopyranose + alpha-D-glucopyranosyl-(1-4)-beta-D-glucopyranose
general acid-base catalytic reaction mechanism
-
(alpha-D-glucopyranosyl-(1-4))n-alpha-D-glucopyranose + H2O = (alpha-D-glucopyranosyl-(1-4))n-2-alpha-D-glucopyranose + alpha-D-glucopyranosyl-(1-4)-beta-D-glucopyranose
Glu367 is important in catalysis, the plant enzyme shows a reaction mechanism different from the bacterial enzyme, overview
(alpha-D-glucopyranosyl-(1-4))n-alpha-D-glucopyranose + H2O = (alpha-D-glucopyranosyl-(1-4))n-2-alpha-D-glucopyranose + alpha-D-glucopyranosyl-(1-4)-beta-D-glucopyranose
mode of action of the exo-amylase
-
(alpha-D-glucopyranosyl-(1-4))n-alpha-D-glucopyranose + H2O = (alpha-D-glucopyranosyl-(1-4))n-2-alpha-D-glucopyranose + alpha-D-glucopyranosyl-(1-4)-beta-D-glucopyranose
mode of action of the exo-amylase
-
(alpha-D-glucopyranosyl-(1-4))n-alpha-D-glucopyranose + H2O = (alpha-D-glucopyranosyl-(1-4))n-2-alpha-D-glucopyranose + alpha-D-glucopyranosyl-(1-4)-beta-D-glucopyranose
mode of action of the exo-amylase
-
(alpha-D-glucopyranosyl-(1-4))n-alpha-D-glucopyranose + H2O = (alpha-D-glucopyranosyl-(1-4))n-2-alpha-D-glucopyranose + alpha-D-glucopyranosyl-(1-4)-beta-D-glucopyranose
mode of action of the exo-amylase
-
(alpha-D-glucopyranosyl-(1-4))n-alpha-D-glucopyranose + H2O = (alpha-D-glucopyranosyl-(1-4))n-2-alpha-D-glucopyranose + alpha-D-glucopyranosyl-(1-4)-beta-D-glucopyranose
mode of action of the exo-amylase
-
(alpha-D-glucopyranosyl-(1-4))n-alpha-D-glucopyranose + H2O = (alpha-D-glucopyranosyl-(1-4))n-2-alpha-D-glucopyranose + alpha-D-glucopyranosyl-(1-4)-beta-D-glucopyranose
mode of action of the exo-amylase
-
(alpha-D-glucopyranosyl-(1-4))n-alpha-D-glucopyranose + H2O = (alpha-D-glucopyranosyl-(1-4))n-2-alpha-D-glucopyranose + alpha-D-glucopyranosyl-(1-4)-beta-D-glucopyranose
mode of action of the exo-amylase
-
(alpha-D-glucopyranosyl-(1-4))n-alpha-D-glucopyranose + H2O = (alpha-D-glucopyranosyl-(1-4))n-2-alpha-D-glucopyranose + alpha-D-glucopyranosyl-(1-4)-beta-D-glucopyranose
mode of action of the exo-amylase
-
(alpha-D-glucopyranosyl-(1-4))n-alpha-D-glucopyranose + H2O = (alpha-D-glucopyranosyl-(1-4))n-2-alpha-D-glucopyranose + alpha-D-glucopyranosyl-(1-4)-beta-D-glucopyranose
mode of action of the exo-amylase
-
(alpha-D-glucopyranosyl-(1-4))n-alpha-D-glucopyranose + H2O = (alpha-D-glucopyranosyl-(1-4))n-2-alpha-D-glucopyranose + alpha-D-glucopyranosyl-(1-4)-beta-D-glucopyranose
mode of action of the exo-amylase
-
(alpha-D-glucopyranosyl-(1-4))n-alpha-D-glucopyranose + H2O = (alpha-D-glucopyranosyl-(1-4))n-2-alpha-D-glucopyranose + alpha-D-glucopyranosyl-(1-4)-beta-D-glucopyranose
mode of action of the exo-amylase
-
(alpha-D-glucopyranosyl-(1-4))n-alpha-D-glucopyranose + H2O = (alpha-D-glucopyranosyl-(1-4))n-2-alpha-D-glucopyranose + alpha-D-glucopyranosyl-(1-4)-beta-D-glucopyranose
mode of action of the exo-amylase
-
(alpha-D-glucopyranosyl-(1-4))n-alpha-D-glucopyranose + H2O = (alpha-D-glucopyranosyl-(1-4))n-2-alpha-D-glucopyranose + alpha-D-glucopyranosyl-(1-4)-beta-D-glucopyranose
mode of action of the exo-amylase
-
(alpha-D-glucopyranosyl-(1-4))n-alpha-D-glucopyranose + H2O = (alpha-D-glucopyranosyl-(1-4))n-2-alpha-D-glucopyranose + alpha-D-glucopyranosyl-(1-4)-beta-D-glucopyranose
mode of action of the exo-amylase
-
(alpha-D-glucopyranosyl-(1-4))n-alpha-D-glucopyranose + H2O = (alpha-D-glucopyranosyl-(1-4))n-2-alpha-D-glucopyranose + alpha-D-glucopyranosyl-(1-4)-beta-D-glucopyranose
roles of Glu186 and Glu380 as general acid and general base catalyst in the catalytic reaction, reaction mechanism involving residue T342
-
(alpha-D-glucopyranosyl-(1-4))n-alpha-D-glucopyranose + H2O = (alpha-D-glucopyranosyl-(1-4))n-2-alpha-D-glucopyranose + alpha-D-glucopyranosyl-(1-4)-beta-D-glucopyranose
roles of Glu186 and Glu380 as general acid and general base catalyst in the catalytic reaction, substrate binding and reaction mechanism
(alpha-D-glucopyranosyl-(1-4))n-alpha-D-glucopyranose + H2O = (alpha-D-glucopyranosyl-(1-4))n-2-alpha-D-glucopyranose + alpha-D-glucopyranosyl-(1-4)-beta-D-glucopyranose
acts on starch, glycogen and related polysaccharides and oligosaccharides producing beta-maltose by an inversion, the term beta relates to the initial anomeric configuration of the free sugar group released and not to the configuration of the linkage hydrolysed
-
-
(alpha-D-glucopyranosyl-(1-4))n-alpha-D-glucopyranose + H2O = (alpha-D-glucopyranosyl-(1-4))n-2-alpha-D-glucopyranose + alpha-D-glucopyranosyl-(1-4)-beta-D-glucopyranose
mode of action of the exo-amylase
-
-
(alpha-D-glucopyranosyl-(1-4))n-alpha-D-glucopyranose + H2O = (alpha-D-glucopyranosyl-(1-4))n-2-alpha-D-glucopyranose + alpha-D-glucopyranosyl-(1-4)-beta-D-glucopyranose
-
-
-
-
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4-nitrophenyl alpha-D-galactoside + H2O
4-nitrophenol + D-galactose
-
-
-
?
4-nitrophenyl alpha-maltopyranoside + H2O
4-nitrophenol + alpha-maltopyranose
-
-
-
?
4-nitrophenyl maltopentaose + H2O
4-nitrophenol + maltopentaose
-
-
-
?
4-nitrophenyl-maltoheptaoside + H2O
?
-
-
-
-
?
4-nitrophenyl-maltopentaoside + H2O
?
-
-
-
-
?
alpha-glucan + H2O
?
-
-
-
?
amylodextrin + H2O
?
-
-
-
-
?
amylopectin + H2O
beta-maltose + ?
amylopectin + H2O
maltose + ?
amylopektin + H2O
?
-
-
-
?
amylose + H2O
beta-maltose
amylose + H2O
maltose
Sorghum sp.
-
from starch
-
-
?
amylose + H2O
maltose + ?
glycogen + H2O
beta-maltose
glycogen + H2O
maltose + ?
maltal + H2O
2-deoxymaltose
-
-
-
?
maltodextrin + H2O
maltose
-
maltodextrins with chain length from 9 to 198 glucose residues
and very small amounts of glucose and maltotriose
?
maltoheptaose + H2O
maltose + D-glucose + ?
the exo-type enzyme can catalyze the successive liberation of beta-maltose from the nonreducing ends of alpha-1,4-linked glucopyranosyl polymers. A phenomenon called multiple or repetitive attack is observed where the enzyme releases several maltose molecules in a single enzyme-substrate complex. The multiple attack action needs the force of enzyme sliding on the substrate. In addition, it is important for the multiple attack that the enzyme and substrate have the characteristics of a stable productive substrate-enzyme complex through a hydrogen bond between the nonreducing end of the substrate and the carboxyl residue of the enzyme
-
-
?
maltooligosaccharide + H2O
?
-
beta-amylase hydrolyzes maltooligosaccharides more readily as their degree of polymerization increases, this being strongest for maltooligosaccharides larger than 13 glucose residues and very weakly for maltotriose, exo-hydrolase that releases beta-maltose from the non-reducing end of alpha-1,4-linked poly- and oligoglucans until the first alpha-1,6-branching point along the substrate molecule is encountered
-
-
?
maltopentaose + H2O
2 maltose + D-glucose
maltose + H2O
?
the enzyme is specific for short alpha-glucans. Similar responses to maltose, glycogen, and starch but not to pullulan
-
-
?
maltotetraose + H2O
2 maltose
maltotriose + H2O
?
-
very poor substrate
-
-
?
maltotriose + H2O
maltose + D-glucose
p-nitrophenyl alpha-D-glucopyranoside + H2O
p-nitrophenol + D-glucose
-
-
-
-
?
p-nitrophenylmaltopentaoside + H2O
?
p-nitrophenylmaltopentaoside + H2O
p-nitrophenol + maltopentaose
catalyzes the release of p-nitrophenol, specific substrate
-
-
?
pullulan + H2O
?
-
-
-
-
?
soluble starch + H2O
maltose + ?
starch + H2O
beta-maltose
starch + H2O
beta-maltose + ?
-
-
-
-
?
additional information
?
-
amylopectin + H2O

?
from potato, active site structure, Glu-186 and Glu-380 play important roles as general acid and base catalyst
-
-
?
amylopectin + H2O
?
-
114.6% of the activity with amylose, soluble starch, amylose and amylopectin are the most suitable substrates, exo-hydrolase that releases beta-maltose from the non-reducing end of alpha-1,4-linked poly- and oligoglucans until the first alpha-1,6-branching point along the substrate molecule is encountered
-
-
?
amylopectin + H2O
?
-
88% of the activity with starch
-
-
?
amylopectin + H2O
?
-
88% of the activity with starch
-
-
?
amylopectin + H2O

beta-maltose + ?
-
-
-
-
?
amylopectin + H2O
beta-maltose + ?
-
-
-
?
amylopectin + H2O
beta-maltose + ?
-
-
-
-
?
amylopectin + H2O
beta-maltose + ?
-
-
and limit dextrin
?
amylopectin + H2O
beta-maltose + ?
-
-
-
-
?
amylopectin + H2O
beta-maltose + ?
-
-
-
-
?
amylopectin + H2O
beta-maltose + ?
-
-
-
-
?
amylopectin + H2O
beta-maltose + ?
-
-
-
-
?
amylopectin + H2O
beta-maltose + ?
-
-
-
?
amylopectin + H2O
beta-maltose + ?
-
-
-
-
?
amylopectin + H2O
beta-maltose + ?
-
-
-
-
?
amylopectin + H2O
beta-maltose + ?
-
-
-
-
?
amylopectin + H2O
beta-maltose + ?
-
-
-
-
?
amylopectin + H2O
beta-maltose + ?
-
-
-
-
?
amylopectin + H2O
beta-maltose + ?
-
-
-
-
?
amylopectin + H2O

maltose + ?
-
-
-
?
amylopectin + H2O
maltose + ?
from potato
-
-
?
amylopectin + H2O
maltose + ?
catalyzes the release of maltose residues, amylopectin and starch are better substrates than amylose
-
-
?
amylopectin + H2O
maltose + ?
-
-
-
-
?
amylopectin + H2O
maltose + ?
-
-
-
?
amylopectin + H2O
maltose + ?
from potato
-
-
?
amylopectin + H2O
maltose + ?
-
from potato
-
-
?
amylopectin + H2O
maltose + ?
Sorghum sp.
-
from starch, preferred substrate
-
-
?
amylopectin + H2O
maltose + ?
the enzyme only releases maltose from polymers such as soluble starch, amylopectin, and glycogen, while maltose is rarely detected from reaction with amylose and pullulan
-
-
?
amylopectin + H2O
maltose + ?
the enzyme only releases maltose from polymers such as soluble starch, amylopectin, and glycogen, while maltose is rarely detected from reaction with amylose and pullulan
-
-
?
amylose + H2O

?
DPn is 16
-
-
?
amylose + H2O
?
-
EX-I, soluble starch, amylose and amylopectin are the most suitable substrates, exo-hydrolase that releases beta-maltose from the non-reducing end of alpha-1,4-linked poly- and oligoglucans until the first alpha-1,6-branching point along the substrate molecule is encountered
-
-
?
amylose + H2O
?
-
79% of the activity with starch
-
-
?
amylose + H2O
?
-
79% of the activity with starch
-
-
?
amylose + H2O

beta-maltose
-
-
-
?
amylose + H2O
beta-maltose
-
-
-
-
?
amylose + H2O
beta-maltose
-
-
-
?
amylose + H2O
beta-maltose
-
-
-
-
?
amylose + H2O
beta-maltose
-
DP = 17
-
-
?
amylose + H2O
beta-maltose
-
-
-
-
?
amylose + H2O
beta-maltose
-
-
-
-
?
amylose + H2O
beta-maltose
-
partly oxidized amylose
-
-
?
amylose + H2O
beta-maltose
-
-
-
-
?
amylose + H2O
beta-maltose
-
-
-
-
?
amylose + H2O
beta-maltose
-
-
-
?
amylose + H2O
beta-maltose
-
-
-
-
?
amylose + H2O
beta-maltose
-
-
-
-
?
amylose + H2O
beta-maltose
-
-
-
-
?
amylose + H2O
beta-maltose
-
-
-
-
?
amylose + H2O

maltose + ?
catalyzes the release of maltose residues, less good substrate than starch and amylopectin
-
-
?
amylose + H2O
maltose + ?
-
-
-
-
?
dextrin + H2O

?
-
-
-
-
?
dextrin + H2O
?
-
13% of the activity with starch
-
-
?
dextrin + H2O
?
-
13% of the activity with starch
-
-
?
glycogen + H2O

?
-
49.4% of the activity with amylose
-
-
?
glycogen + H2O
?
the enzyme is specific for short alpha-glucans. Similar responses to maltose, glycogen, and starch but not to pullulan
-
-
?
glycogen + H2O

beta-maltose
-
-
-
?
glycogen + H2O
beta-maltose
-
-
-
-
?
glycogen + H2O
beta-maltose
-
-
and limit dextrin
?
glycogen + H2O
beta-maltose
-
from oyster
-
-
?
glycogen + H2O
beta-maltose
-
-
-
-
?
glycogen + H2O
beta-maltose
-
type III and type VIII
-
-
?
glycogen + H2O
beta-maltose
-
-
-
-
?
glycogen + H2O

maltose + ?
the enzyme only releases maltose from polymers such as soluble starch, amylopectin, and glycogen, while maltose is rarely detected from reaction with amylose and pullulan
-
-
?
glycogen + H2O
maltose + ?
the enzyme only releases maltose from polymers such as soluble starch, amylopectin, and glycogen, while maltose is rarely detected from reaction with amylose and pullulan
-
-
?
maltoheptaose + H2O

?
-
-
-
-
?
maltoheptaose + H2O
?
-
-
-
-
?
maltoheptaose + H2O
?
-
34.6% of the activity with amylose
-
-
?
maltoheptaose + H2O
?
-
-
-
-
?
maltohexaose + H2O

?
-
-
-
-
?
maltohexaose + H2O
?
-
-
-
-
?
maltohexaose + H2O
?
-
23.3% of the activity with amylose
-
-
?
maltopentaose + H2O

2 maltose + D-glucose
substrate/product binding structure, sugar subsite conformations, overview
-
-
?
maltopentaose + H2O
2 maltose + D-glucose
the enzyme displays dual hydrolysis activity toward alpha-1,4- and alpha-1,6-glycosidic linkages, the catalytic efficiency of 6-O-maltosyl-beta-cyclodextrin is 16fold higher than that of maltotriose. Compared to the kcat/Km value toward maltotriose, the values for longer substrates such as maltotetraose and maltopentaose are negligible
-
-
?
maltopentaose + H2O
2 maltose + D-glucose
the enzyme displays dual hydrolysis activity toward alpha-1,4- and alpha-1,6-glycosidic linkages, the catalytic efficiency of 6-O-maltosyl-beta-cyclodextrin is 16fold higher than that of maltotriose. Compared to the kcat/Km value toward maltotriose, the values for longer substrates such as maltotetraose and maltopentaose are negligible
-
-
?
maltopentaose + H2O

?
-
-
-
-
?
maltopentaose + H2O
?
beta-amylase is an exo-enzyme that catalyzes the hydrolysis of the alpha-1,4-glucosidic linkage of the substrate liberating beta-maltose from the non-reducing end, Glu-172 and Glu-367 are catalytic residues, binding mode of substrate, substrate recognition mechanism, enzyme structure
-
-
?
maltopentaose + H2O
?
-
beta-amylase is an inverting enzyme that hydrolyzes the alpha-1,