Cloned (Comment) | Organism |
---|---|
- |
Escherichia coli |
Protein Variants | Comment | Organism |
---|---|---|
N74X | overexpression of a series of mutant enzymes. Site-directed mutagenesis of Asn74 shows that this residue plays a role in catalysis of nitrogen transfer from Gln. Replacement of Arg-30 by an Ala residue yields a mutant enzyme for which the apparent Km for Gln is increased in the Gln-dependent synthesis of Asn. In addition ATP-dependent stimulation of the glutaminase activity is modified or completely eliminated when Arg-30 is replaced by other amino acids | Escherichia coli |
R30A | overexpression of a series of mutant enzymes. Site-directed mutagenesis of Asn74 shows that this residue plays a role in catalysis of nitrogen transfer from Gln. Replacement of Arg-30 by an Ala residue yields a mutant enzyme for which the apparent Km for Gln is increased in the Gln-dependent synthesis of Asn. In addition ATP-dependent stimulation of the glutaminase activity is modified or completely eliminated when Arg-30 is replaced by other amino acids | Escherichia coli |
R325A | a number of site-specific AS-B mutants. When Arg325 is replaced by Ala or Lys, the resulting mutant enzymes possess no detectable Asn synthetase activity. Mutation of Thr322 and Thr323 also produce enzymes with altered kinetic properties, suggesting that these Thr are involved in Asp binding and/or stabilization of intermediates en route to beta-aspartyl-AMP | Escherichia coli |
R325L | a number of site-specific AS-B mutants. When Arg325 is replaced by Ala or Lys, the resulting mutant enzymes possess no detectable Asn synthetase activity. Mutation of Thr322 and Thr323 also produce enzymes with altered kinetic properties, suggesting that these Thr are involved in Asp binding and/or stabilization of intermediates en route to beta-aspartyl-AMP | Escherichia coli |
T322X | a number of site-specific AS-B mutants. When Arg325 is replaced by Ala or Lys, the resulting mutant enzymes possess no detectable Asn synthetase activity. Mutation of Thr322 and Thr323 also produce enzymes with altered kinetic properties, suggesting that these Thr are involved in Asp binding and/or stabilization of intermediates en route to beta-aspartyl-AMP | Escherichia coli |
T323X | a number of site-specific AS-B mutants. When Arg325 is replaced by Ala or Lys, the resulting mutant enzymes possess no detectable Asn synthetase activity. Mutation of Thr322 and Thr323 also produce enzymes with altered kinetic properties, suggesting that these Thr are involved in Asp binding and/or stabilization of intermediates en route to beta-aspartyl-AMP | Escherichia coli |
KM Value [mM] | KM Value Maximum [mM] | Substrate | Comment | Organism | Structure |
---|---|---|---|---|---|
additional information | - |
additional information | Km-values of mutant enzymes R30A, R30K, N74A, N74Q, and N79A | Escherichia coli | |
0.26 | - |
L-glutamic acid gamma-monohydroxamate | ATP, wild-type enzyme, Gln-dependent activity | Escherichia coli | |
0.66 | - |
Gln | wild-type enzyme | Escherichia coli | |
0.85 | - |
Asp | Asp, wild-type enzyme, Gln-dependent activity | Escherichia coli |
Organism | UniProt | Comment | Textmining |
---|---|---|---|
Escherichia coli | - |
wild-type and mutant enzymes R30A, R30K, N74A, N74Q, N79A | - |
Substrates | Comment Substrates | Organism | Products | Comment (Products) | Rev. | Reac. |
---|---|---|---|---|---|---|
ATP + L-Asp + L-Gln | - |
Escherichia coli | AMP + diphosphate + Asn + Glu | - |
? | |
L-Glutamic acid gamma-monohydroxamate + H2O | - |
Escherichia coli | Hydroxylamine + Glu | - |
? | |
additional information | enzyme has inherent glutaminase activity | Escherichia coli | ? | - |
? |
Turnover Number Minimum [1/s] | Turnover Number Maximum [1/s] | Substrate | Comment | Organism | Structure |
---|---|---|---|---|---|
additional information | - |
additional information | turnover-numbers of mutant enzymes R30A, R30K, N74A, N74Q, and N79A | Escherichia coli | |
0.57 | - |
Asp | wild-type | Escherichia coli | |
0.59 | - |
Gln | wild-type | Escherichia coli | |
0.8 | - |
ATP | wild-type | Escherichia coli |