Protein Variants | Comment | Organism |
---|---|---|
R310K | absorption spectra similar to wild-type. 20fold decrease of kred-value | Rhodobacter capsulatus |
R310K | kred, the limiting rate of enzyme reduction by substrate at high substrate concentration is 20-fold decreased | Rhodobacter capsulatus |
R310M | absorption spectra similar to wild-type. 20000fold decrease of kred-value | Rhodobacter capsulatus |
R310M | kred, the limiting rate of enzyme reduction by substrate at high substrate concentration is 20000-fold decreased | Rhodobacter capsulatus |
KM Value [mM] | KM Value Maximum [mM] | Substrate | Comment | Organism | Structure |
---|---|---|---|---|---|
additional information | - |
additional information | rapid reaction kinetic parameters for substrates xanthine, 2-thioxanthine, 6-thioxanthine, 1-methylxanthine, 2-hydroxy-6-methylpurine, and 2,6-diaminopurine, in wild-type and mutants R310K and R310M | Rhodobacter capsulatus |
Organism | UniProt | Comment | Textmining |
---|---|---|---|
Rhodobacter capsulatus | - |
- |
- |
Substrates | Comment Substrates | Organism | Products | Comment (Products) | Rev. | Reac. |
---|---|---|---|---|---|---|
1-methylxanthine + NAD+ + H2O | 10fold reduced kred-value compared to xanthine | Rhodobacter capsulatus | 1-methylurate + NADH + H+ | - |
? | |
1-methylxanthine + NAD+ + H2O | rather less effective than xanthine as a substrate | Rhodobacter capsulatus | 1-methylurate + NADH + H+ | - |
? | |
2,6-diaminopurine + NAD+ + H2O | poor substrate | Rhodobacter capsulatus | ? + NADH + H+ | - |
? | |
2-hydroxy-6-methylpurine + NAD+ + H2O | poor substrate | Rhodobacter capsulatus | ? + NADH + H+ | - |
? | |
2-thioxanthine + NAD+ + H2O | good substrate | Rhodobacter capsulatus | 2-thiourate + NADH + H+ | - |
? | |
2-thioxanthine + NAD+ + H2O | effective substrate | Rhodobacter capsulatus | 2-thiourate + NADH + H+ | - |
? | |
6-thioxanthine + NAD+ + H2O | good substrate | Rhodobacter capsulatus | ? + NADH + H+ | - |
? | |
6-thioxanthine + NAD+ + H2O | effective substrate | Rhodobacter capsulatus | 6-thiourate + NADH + H+ | - |
? | |
additional information | model in which good substrates are bound correctly in the active site in an orientation that allows Arg310 to stabilize the transition state for the first step of the overall reaction via an electrostatic interaction at the C-6 position, thereby accelerating the reaction rate. Poor substrates bind upside down relative to this correct orientation and are unable to avail themselves of the additional catalytic power provided by Arg310 in wild-type enzyme but are significantly less affected by mutations at this position. Analysis of rapid reaction kinetic parameters | Rhodobacter capsulatus | ? | - |
? | |
xanthine + NAD+ + H2O | - |
Rhodobacter capsulatus | urate + NADH + H+ | - |
? |