Protein Variants | Comment | Organism |
---|---|---|
F109M | both substrate affinity and kcat are significantly compromised. The specificity for 2-ketobutyrate as acceptor is not altered | Escherichia coli |
V375A | slightly reduced kcat value with a moderate increase of the apparent KM of pyruvate. The specificity for 2-ketobutyrate as acceptor is not altered | Escherichia coli |
V375I | slightly reduced kcat value with a moderate increase of the apparent KM of pyruvate. The specificity for 2-ketobutyrate as acceptor is not altered | Escherichia coli |
KM Value [mM] | KM Value Maximum [mM] | Substrate | Comment | Organism | Structure |
---|---|---|---|---|---|
6.6 | - |
pyruvate | wild-type, pH 7.6, 37°C | Escherichia coli | |
7.3 | - |
pyruvate | mutant V375I, pH 7.6, 37°C | Escherichia coli | |
9.1 | - |
2-oxobutanoate | mutant V375A, pH 7.6, 37°C | Escherichia coli | |
13.8 | - |
pyruvate | mutant V375A, pH 7.6, 37°C | Escherichia coli | |
17.3 | - |
pyruvate | mutant F109M, pH 7.6, 37°C | Escherichia coli | |
300 | - |
2-oxobutanoate | wild-type, pH 7.6, 37°C | Escherichia coli |
Organism | UniProt | Comment | Textmining |
---|---|---|---|
Escherichia coli | - |
acetohydroxy acid synthase isozyme II | - |
Specific Activity Minimum [µmol/min/mg] | Specific Activity Maximum [µmol/min/mg] | Comment | Organism |
---|---|---|---|
3.4 | - |
mutant F109M, pH 7.6, 37°C | Escherichia coli |
8.2 | - |
mutant V375A, pH 7.6, 37°C | Escherichia coli |
22.7 | - |
mutant V375I, pH 7.6, 37°C | Escherichia coli |
34.3 | - |
wild-type, pH 7.6, 37°C | Escherichia coli |
Substrates | Comment Substrates | Organism | Products | Comment (Products) | Rev. | Reac. |
---|---|---|---|---|---|---|
2 pyruvate | 60fold higher specificity for 2-ketobutyrate over pyruvate as acceptor | Escherichia coli | 2-acetolactate + CO2 | - |
? | |
2-oxobutanoate + pyruvate | 60fold higher specificity for 2-ketobutyrate over pyruvate as acceptor | Escherichia coli | 2-hydroxy-2-methyl-3-oxopentanoate + CO2 | - |
? | |
additional information | a valine and a phenylalanine residue hydrophobically interact with the methyl substituent of pyruvate. A mutation of either Val375 or Phe109 is detrimental for unimolecular catalytic steps in which tetrahedral intermediates are involved, such as substrate addition to the cofactor and product liberation. Val375 and Phe109 to not only conjointly mediate substrate binding and specificity but moreover to ensure a proper orientation of the donor substrate and intermediates for correct orbital alignment in multiple transition states | Escherichia coli | ? | - |
? |
Synonyms | Comment | Organism |
---|---|---|
AHAS | - |
Escherichia coli |
Turnover Number Minimum [1/s] | Turnover Number Maximum [1/s] | Substrate | Comment | Organism | Structure |
---|---|---|---|---|---|
3.3 | - |
2-oxobutanoate | wild-type, pH 7.6, 37°C | Escherichia coli | |
3.9 | - |
pyruvate | mutant F109M, pH 7.6, 37°C | Escherichia coli | |
9.6 | - |
pyruvate | mutant V375A, pH 7.6, 37°C | Escherichia coli | |
11.9 | - |
2-oxobutanoate | mutant V375A, pH 7.6, 37°C | Escherichia coli | |
26.6 | - |
pyruvate | mutant V375I, pH 7.6, 37°C | Escherichia coli | |
40.3 | - |
pyruvate | wild-type, pH 7.6, 37°C | Escherichia coli |
kcat/KM Value [1/mMs-1] | kcat/KM Value Maximum [1/mMs-1] | Substrate | Comment | Organism | Structure |
---|---|---|---|---|---|
0.011 | - |
2-oxobutanoate | wild-type, pH 7.6, 37°C | Escherichia coli | |
0.23 | - |
pyruvate | mutant F109M, pH 7.6, 37°C | Escherichia coli | |
0.7 | - |
pyruvate | mutant V375A, pH 7.6, 37°C | Escherichia coli | |
1.3 | - |
2-oxobutanoate | mutant V375A, pH 7.6, 37°C | Escherichia coli | |
3.6 | - |
pyruvate | mutant V375I, pH 7.6, 37°C | Escherichia coli | |
6.1 | - |
pyruvate | wild-type, pH 7.6, 37°C | Escherichia coli |