Effect of pyrophosphate and orotidine monophosphate on cytosine deaminase regulatory properties

The maximal velocity of the reaction (Vmax) and the half-saturation constant (K0.5) values of the S. typhimurium cytosine deaminase were altered in the presence of its effectors, pyrophosphate and orotidine monophosphate. From the kinetics of orotidine monophosphate inhibition of cytosine deaminase, it was characterized as a mixed-type noncompetitive inhibitor.