EC Number   |
KM Value [mM] |
KM Value Maximum [mM] |
Substrate |
Reference |
|---|
    1.17.1.4 | -999 |
- |
? |
KM (mM) (cyanoacetylhydrazone 2-formylquinoxaline-1,4-dioxide) (pH 7.4, 37°C), wild-type: 0.0582, mutant G47A: 0.06568, mutant N352A: 0.0601, mutant S360P: 0.09353, mutant R427E: 0.02086, mutant D430H: 0.06468, mutant D431A: 0.06129, mutant S1227A: 0.148, mutant K1230A: 0.162 |
728624 |
| 1.17.1.4 | -999 |
- |
more |
2-position hydroxylation is crucial for 8-position hydroxylation. Stopped-flow studies indicate that the rate-limiting step of the reductive half-reaction is not electron transfer from the xanthine substrate to the molybdenum center, but product release |
703626 |
| 1.17.1.4 | -999 |
- |
more |
kinetics in presence and absence of cellular retinol binding proteins, apo-CRBP and apo-CRABP, overview |
704842 |
| 1.17.1.4 | -999 |
- |
more |
Km-value is 0.0025 mg/ml xanthine |
688044 |
| 1.17.1.4 | -999 |
- |
more |
Michaelis-Menten steady-state kinetics, overview |
744255 |
| 1.17.1.4 | -999 |
- |
more |
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 |
674793 |
| 1.17.1.4 | -999 |
- |
more |
steady-state kinetics and reductive half-reaction, stopped flow kinetics, kinetic analysis of wild-type and mutant xanthine dehydrogenases, overview. kred, the limiting rate constant for reduction at high [xanthine], is significantly compromised in the mutant variant E232Q, a result that is inconsistent with Glu232 being neutral in the active site of the wild-type enzyme. The ionized Glu232 of wild-type enzyme plays an important role in catalysis by discriminating against the monoanionic form of substrate, effectively increasing the pKa of the substrate by two pH units and ensuring that at physiological pH the neutral form of the substrate predominates in the Michaelis complex. The product release is principally rate-limiting in catalysis. The disparity in rate constants for the chemical step of the reaction and product release is not as great in the bacterial enzyme as compared with the vertebrate forms. The faster turnover observed with the bacterial enzyme isdue to a faster rate constant for product release than is seen with the vertebrate enzyme |
745314 |
| 1.17.1.4 | -999 |
- |
more |
steady-state kinetics of DTT-treated and untreated C-terminally truncated enzyme mutant |
744875 |
| 1.17.1.4 | 0.0003 |
- |
xanthine |
electron acceptor: NAD+ |
644588 |
| 1.17.1.4 | 0.00083 |
- |
methylene blue |
electron donor: 2-amino-4-hydroxy-pterine |
644595 |
