Cloned (Comment) | Organism |
---|---|
wild-type and mutant enzymes, expression in Escherichia coli BL21(DE3) | Bacillus cereus |
Crystallization (Comment) | Organism |
---|---|
- |
Bacillus cereus |
Protein Variants | Comment | Organism |
---|---|---|
additional information | mutation of two of the three carbohydrate-binding sites aside from the active site: Site2 in domain B and Site1 in domain C | Bacillus cereus |
S235A | binding parameters to raw corn starch, kinetic parameters for the hydrolysis of amylose, 88% of wild-type activity with soluble starch as substrate | Bacillus cereus |
S235A/Y249A | double mutant, binding parameters to raw corn starch, kinetic parameters for the hydrolysis of amylose, 63% of wild-type activity with soluble starch as substrate | Bacillus cereus |
S235A/Y249A/W449F/W495F | quadruple mutant, kinetic parameters for the hydrolysis of amylose, 51% of wild-type activity with soluble starch as substrate | Bacillus cereus |
W449F | binding parameters to raw corn starch | Bacillus cereus |
W449F/W495F | double mutant, binding parameters to raw corn starch, kinetic parameters for the hydrolysis of amylose, 61% of wild-type activity with soluble starch as substrate | Bacillus cereus |
W495F | binding parameters to raw corn starch | Bacillus cereus |
W51F | beta-amylase mutant | Bacillus cereus |
Y249A | binding parameters to raw corn starch, kinetic parameters for the hydrolysis of amylose, 80% of wild-type activity with soluble starch as substrate | Bacillus cereus |
Inhibitors | Comment | Organism | Structure |
---|---|---|---|
cyclohexaamylose | alpha-CD, competitive inhibitor | Bacillus cereus | |
maltitol | behaves as a mixed-type or competitive inhibitor depending on the chain length of the substrate, inhibition mechanism, binds to Site2 in domain B and forms an abortive ESI complex when amylose is used as substrate | Bacillus cereus | |
O-alpha-D-xylopyranosyl(1-4)O-alpha-D-glucopyranosyl(1-4)O-alpha-D-glucopyranoside | mixed-type inhibition, two molecules bind to enzyme | Bacillus cereus |
KM Value [mM] | KM Value Maximum [mM] | Substrate | Comment | Organism | Structure |
---|---|---|---|---|---|
additional information | - |
additional information | binding parameters of wild-type and mutant enzymes to raw corn starch | Bacillus cereus | |
0.6 | - |
amylose | pH 7, 25°C, DPn: 16, S235A/Y249A/W449F/W495F quadruple mutant | Bacillus cereus | |
0.61 | - |
amylose | pH 7, 25°C, DPn: 16, W449F/W495F double mutant | Bacillus cereus | |
0.65 | - |
amylose | pH 7, 25°C, DPn: 16, S235A/Y249A double mutant | Bacillus cereus | |
0.7 | - |
amylose | pH 7, 25°C, DPn: 16, S235A mutant | Bacillus cereus | |
0.71 | - |
amylose | pH 7, 25°C, DPn: 16, Y249A mutant | Bacillus cereus | |
0.72 | - |
amylose | pH 7, 25°C, DPn: 16, wild-type enzyme | Bacillus cereus |
Molecular Weight [Da] | Molecular Weight Maximum [Da] | Comment | Organism |
---|---|---|---|
58300 | - |
x * 58300, Western blot analysis | Bacillus cereus |
Organism | UniProt | Comment | Textmining |
---|---|---|---|
Bacillus cereus | P36924 | var. mycoides | - |
Purification (Comment) | Organism |
---|---|
recombinant wild-type and mutant enzymes | Bacillus cereus |
Substrates | Comment Substrates | Organism | Products | Comment (Products) | Rev. | Reac. |
---|---|---|---|---|---|---|
amylose + H2O | DPn is 16 | Bacillus cereus | ? | - |
? | |
maltopentaose + H2O | binding mode of substrate in the active site | Bacillus cereus | ? | - |
? | |
additional information | no hydrolysis of alpha-1,6-glucosidic linkages | Bacillus cereus | ? | - |
? | |
starch + H2O | catalyzes the hydrolysis of alpha-1,4-glucosidic linkages of soluble starch, and liberates beta-anomeric maltose from the nonreducing ends, exo-acting enzyme, composed of two functional domains, a catalytic domain: domains A and B, and starch-binding domain: domain C, beta-amylase has three carbohydrate-binding sites aside from the active site: two in domain B named Site2 and Site3, one in domain C named Site1, roles of these sites in the catalytic reaction and raw starch-binding, beta-amylase hardly hydrolyzes raw starch from wheat, corn, potato or sweet potato, but binds to it strongly | Bacillus cereus | ? | - |
? |
Subunits | Comment | Organism |
---|---|---|
? | x * 58300, Western blot analysis | Bacillus cereus |
More | enzyme is composed of two functional domains, a catalytic domain: domains A and B, and starch-binding domain: domain C, beta-amylase has three carbohydrate-binding sites aside from the active site: two in domain B named Site2 and Site3, one in domain C named Site1, roles of these sites in the catalytic reaction and raw starch-binding | Bacillus cereus |
Temperature Optimum [°C] | Temperature Optimum Maximum [°C] | Comment | Organism |
---|---|---|---|
25 | - |
assay at | Bacillus cereus |
Turnover Number Minimum [1/s] | Turnover Number Maximum [1/s] | Substrate | Comment | Organism | Structure |
---|---|---|---|---|---|
additional information | - |
additional information | - |
Bacillus cereus |
pH Optimum Minimum | pH Optimum Maximum | Comment | Organism |
---|---|---|---|
7 | - |
assay at | Bacillus cereus |
Ki Value [mM] | Ki Value maximum [mM] | Inhibitor | Comment | Organism | Structure |
---|---|---|---|---|---|
0.45 | - |
O-alpha-D-xylopyranosyl(1-4)O-alpha-D-glucopyranosyl(1-4)O-alpha-D-glucopyranoside | pH 7, 25°C, wild-type enzyme, amylose as substrate | Bacillus cereus | |
0.8 | - |
cyclohexaamylose | pH 7, 25°C, wild-type enzyme, amylose as substrate | Bacillus cereus | |
2.8 | - |
maltitol | pH 7, 25°C, wild-type enzyme, amylose as substrate | Bacillus cereus | |
3.1 | - |
maltitol | pH 7, 25°C, wild-type enzyme, maltopentaose as substrate | Bacillus cereus | |
5.1 | - |
maltitol | pH 7, 25°C, S235A/Y249A double mutant, amylose as substrate | Bacillus cereus | |
5.7 | - |
maltitol | pH 7, 25°C, S235A/Y249A/W449F/W495F quadruple mutant, amylose as substrate | Bacillus cereus |