Crystallization (Comment) | Organism |
---|---|
HSAmy and HSAmy-ar both show characteristics of a protein with ordered secondary structures, suggesting that the overall conformation of HSamy still retains in the mutant HSAmy-ar. Single or double mutations also do not alter the overall conformation of the enzyme | Homo sapiens |
Protein Variants | Comment | Organism |
---|---|---|
W134A/W203A/Y276A/W284A/W316A/W388A | HSAmy-ar, multiple mutant, 10fold reduction of activity compared with wild-type enzyme and also sigificant reductaion of starch binding activity | Homo sapiens |
W203A | 2fold reduction of activity compared to the wild-type enzyme, similar starch-binding activity like the wild-type enzyme | Homo sapiens |
W284A | similar specific activity and similar starch-binding activity like the wild-type enzyme | Homo sapiens |
W316A/W388A | similar specific activity and similar starch-binding activity like the wild-type enzyme | Homo sapiens |
Y276/W284A | similar specific activity and similar starch-binding activity like the wild-type enzyme | Homo sapiens |
Y276A | similar specific activity and similar starch-binding activity like the wild-type enzyme | Homo sapiens |
Organism | UniProt | Comment | Textmining |
---|---|---|---|
Homo sapiens | P04745 | - |
- |
Source Tissue | Comment | Organism | Textmining |
---|---|---|---|
saliva | - |
Homo sapiens | - |
Specific Activity Minimum [µmol/min/mg] | Specific Activity Maximum [µmol/min/mg] | Comment | Organism |
---|---|---|---|
additional information | - |
the specific activity of the mutant HSAmy-ar decreases by 87% (a 10fold reduction) compared to the wild-type HSAmy, indicating that the absence of saccharide-binding ability at the secondary binding sites in HSAmy-ar has resulted in a significant reduction in enzyme activity. The activity is also affected by about 2fold when the aromatic residue at position 203 is mutated. Among the single or douible mutants studied, W203A exhibit the least activity against starch hydrolsis. The mutation at position W284 do not alter the specific activity to any significant extent. Double mutations at the residues W316 and E388 also do not affect activity | Homo sapiens |
Substrates | Comment Substrates | Organism | Products | Comment (Products) | Rev. | Reac. |
---|---|---|---|---|---|---|
maltoheptaoside + H2O | all mutants possess the ability to hydrolyze heptasaccharide substrates and generate a similar product profile like the wild-type enzyme. The three mutants W203A, W284A, HSAmy-ar generate less products. They require higher enzyme concentration (600 nM vs. 60 nM for HSAmy and the other mutants) and more time (5 min vs. 2 min) 25°C, pH 6.9 | Homo sapiens | ? | - |
? | |
maltopentaoside + H2O | all mutants possess the ability to hydrolyze pentasaccharide substrates and generate a similar product profile like the wild-type enzyme. The three mutants W203A, W284A, HSAmy-ar generate less products. They require higher enzyme concentration (600 nM vs. 60 nM for HSAmy and the other mutants) and more time (5 min vs. 2 min) 25°C, pH 6.9 | Homo sapiens | ? | - |
? | |
starch + H2O | 25°C, pH 6.9 | Homo sapiens | ? | - |
? |
Synonyms | Comment | Organism |
---|---|---|
HSAmy | - |
Homo sapiens |
HSAmy-ar | multiple mutant enzyme | Homo sapiens |
Temperature Optimum [°C] | Temperature Optimum Maximum [°C] | Comment | Organism |
---|---|---|---|
25 | - |
assay at | Homo sapiens |
pH Optimum Minimum | pH Optimum Maximum | Comment | Organism |
---|---|---|---|
6.9 | - |
assay at | Homo sapiens |