Cloned (Comment) | Organism |
---|---|
cloning of the maltase gene from strain 727-14C, cloning from a cDNA library and amino acid sequence determination, expression of wild-type enzyme in Escherichia coli strain KP3998, expression of chimeric maltase/isomaltase mutant enzymes in Escherichia coli strain KP3998 | Saccharomyces cerevisiae |
Protein Variants | Comment | Organism |
---|---|---|
additional information | construction of chimeric maltase/isomaltase mutant enzymes, mutants D215A, V216T, G217A, and S218G of isomaltase are constructed mimicking the maltase sequence, isomaltase mutant V216T shows the same substrate specificity for maltose and isomaltose, while the wild-type isomaltase is not active with maltose and the wild-type maltase is not active with isomaltose, overview | Saccharomyces cerevisiae |
KM Value [mM] | KM Value Maximum [mM] | Substrate | Comment | Organism | Structure |
---|---|---|---|---|---|
0.31 | - |
4-nitrophenyl alpha-D-glucopyranoside | pH 7.0, 30°C, recombinant wild-type enzyme | Saccharomyces cerevisiae |
Natural Substrates | Organism | Comment (Nat. Sub.) | Natural Products | Comment (Nat. Pro.) | Rev. | Reac. |
---|---|---|---|---|---|---|
maltose + H2O | Saccharomyces cerevisiae | - |
alpha-D-glucose + D-glucose | - |
? |
Organism | UniProt | Comment | Textmining |
---|---|---|---|
Saccharomyces cerevisiae | - |
strains D-346, ATCC 56960, and 727-14C, ATCC 56959 | - |
Purification (Comment) | Organism |
---|---|
recombinant enzyme from Escherichia coli by ion exchange and hydroxyapatite chromatography | Saccharomyces cerevisiae |
Reaction | Comment | Organism | Reaction ID |
---|---|---|---|
maltotetraose + 3 H2O = 4 alpha-D-glucose | Val216 determines the substrate specificity of the yeast enzyme, active site structure modelling | Saccharomyces cerevisiae |
Specific Activity Minimum [µmol/min/mg] | Specific Activity Maximum [µmol/min/mg] | Comment | Organism |
---|---|---|---|
70 | - |
purified recombinant wild-type enzyme, substrate maltose | Saccharomyces cerevisiae |
132 | - |
purified recombinant wild-type enzyme, substrate 4-nitrophenyl alpha-D-glucoside | Saccharomyces cerevisiae |
Substrates | Comment Substrates | Organism | Products | Comment (Products) | Rev. | Reac. |
---|---|---|---|---|---|---|
4-nitrophenyl alpha-D-glucopyranoside + H2O | - |
Saccharomyces cerevisiae | 4-nitrophenol + alpha-D-glucose | - |
? | |
maltose + H2O | - |
Saccharomyces cerevisiae | alpha-D-glucose + D-glucose | - |
? | |
additional information | no activity with isomaltose, Val216 decides the enzyme's substrate specificity | Saccharomyces cerevisiae | ? | - |
? |
Synonyms | Comment | Organism |
---|---|---|
maltase | - |
Saccharomyces cerevisiae |