Protein Variants | Comment | Organism |
---|---|---|
E47A | about 5% of wild-type activity | Escherichia coli |
E47Q | about 5% of wild-type activity | Escherichia coli |
Q110A | about 3% of wild-type activity | Escherichia coli |
Q110E | about 1.5% of wild-type activity | Escherichia coli |
Q110H | about 15% of wild-type activity | Escherichia coli |
Q110N | about 8% of wild-type activity | 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 | |
7.1 | - |
pyruvate | mutant E47A, pH 7.6, 37°C | Escherichia coli | |
7.7 | - |
pyruvate | mutant E47Q, pH 7.6, 37°C | Escherichia coli | |
29.5 | - |
pyruvate | mutant Q110N, pH 7.6, 37°C | Escherichia coli | |
30.2 | - |
pyruvate | mutant Q110A, pH 7.6, 37°C | Escherichia coli | |
40.4 | - |
pyruvate | mutant Q110H pH 7.6, 37°C | Escherichia coli | |
110.6 | - |
pyruvate | mutant Q110E, pH 7.6, 37°C | Escherichia coli |
Organism | UniProt | Comment | Textmining |
---|---|---|---|
Escherichia coli | - |
isoform AHAS II | - |
Substrates | Comment Substrates | Organism | Products | Comment (Products) | Rev. | Reac. |
---|---|---|---|---|---|---|
2 pyruvate | - |
Escherichia coli | 2-acetolactate + CO2 | - |
? | |
2-oxobutanoate + pyruvate | - |
Escherichia coli | 2-hydroxy-2-methyl-3-oxopentanoate + CO2 | - |
? | |
additional information | residue Glu47 has a crucial catalytic role for it in the carboligation of the acceptor and the hydroxyethyl-thiamine diphosphate enamine intermediate. The Glu47-cofactor proton shuttle acts in concert with Gln110 in the carboligation. Either the transient oxyanion on the acceptor carbonyl is stabilized by H-bonding to the glutamine side chain, or carboligation involves glutamine tautomerization and the elementary reactions of addition and protonation occur in a concerted manner. Gln110 and Glu47 have global catalytic roles, being engaged in all major bond-breaking and bond-making steps. Lys159 has a minor effect on the kinetics and specificity of isoform AHAS II, far less than does Arg276,which influences the specificity for a 2-ketoacid as a second substrate. His251 has a large effect on donor substrate binding, but this effect masks any other effects of replacement of His251 | Escherichia coli | ? | - |
? |
Synonyms | Comment | Organism |
---|---|---|
AHAS II | - |
Escherichia coli |
Turnover Number Minimum [1/s] | Turnover Number Maximum [1/s] | Substrate | Comment | Organism | Structure |
---|---|---|---|---|---|
0.4 | - |
pyruvate | mutant Q110E, pH 7.6, 37°C | Escherichia coli | |
1.6 | - |
pyruvate | mutant E47Q, pH 7.6, 37°C | Escherichia coli | |
1.6 | - |
pyruvate | mutant Q110H pH 7.6, 37°C | Escherichia coli | |
2.7 | - |
pyruvate | mutant E47A, pH 7.6, 37°C | Escherichia coli | |
2.7 | - |
pyruvate | mutant Q110A, pH 7.6, 37°C | Escherichia coli | |
5.8 | - |
pyruvate | mutant Q110N, pH 7.6, 37°C | Escherichia coli | |
40.3 | - |
pyruvate | wild-type, pH 7.6, 37°C | Escherichia coli |
Cofactor | Comment | Organism | Structure |
---|---|---|---|
thiamine diphosphate | residue Glu47 is involved in cofactor activation, substrate binding, and product elimination and plays a crucial catalytic role in the carboligation of the acceptor and the hydroxyethyl-thiamine diphosphate enamine intermediate. The Glu47-cofactor proton shuttle acts in concert with Gln110 in the carboligation | Escherichia coli |
kcat/KM Value [1/mMs-1] | kcat/KM Value Maximum [1/mMs-1] | Substrate | Comment | Organism | Structure |
---|---|---|---|---|---|
0.004 | - |
pyruvate | mutant Q110E, pH 7.6, 37°C | Escherichia coli | |
0.04 | - |
pyruvate | mutant Q110H pH 7.6, 37°C | Escherichia coli | |
0.09 | - |
pyruvate | mutant Q110A, pH 7.6, 37°C | Escherichia coli | |
0.2 | - |
pyruvate | mutant Q110N, pH 7.6, 37°C | Escherichia coli | |
0.208 | - |
pyruvate | mutant E47Q, pH 7.6, 37°C | Escherichia coli | |
0.375 | - |
pyruvate | mutant E47A, pH 7.6, 37°C | Escherichia coli | |
6.1 | - |
pyruvate | wild-type, pH 7.6, 37°C | Escherichia coli |