6.3.4.2 additional information - additional information xanthine and related compounds inhibit CTPS activity with IC50 = 0.16-0.58 mM. The presence of an 8-oxo function enhances the inhibition to IC50 = 0.060-0.121 mM. Raising the pH from 8.0 to 8.5 results in slightly increased inhibition of NH3-dependent CTP formation by the xanthines 702613 6.3.4.2 0.04 - CTP wild-type, pH 8.1, 37°C 715549 6.3.4.2 0.042 - CTP wild-type, pH 8.1, 37°C 715549 6.3.4.2 0.045 - CTP mutant S571A, pH 8.1, 37°C 715549 6.3.4.2 0.05 - CTP IC50: 0.05 mM 649000 6.3.4.2 0.057 - CTP C-terminal deletion mutant, pH 8.1, 37°C 715549 6.3.4.2 0.06 - uric acid pH 8.0, Gln-dependent CTP formation 702613 6.3.4.2 0.063 - 3,7-dimethyluric acid pH 8.0, Gln-dependent CTP formation 702613 6.3.4.2 0.067 - 1,3,7-trimethyluric acid pH 8.0, Gln-dependent CTP formation 702613 6.3.4.2 0.07 - 1,3,7-trimethyluric acid pH 8.0, NH3-dependent CTP formation 702613