Fluoride inhibition of inorganic pyrophosphatase I. Kinetic studies in A Mg2+-PPi system using a new continuous enzyme assay

摘要: Reversible inhibition of bakers' yeast inorganic pyrophosphatase (EC 3.6.1.1) by fluoride has been studied as a function substrate, metal-ion activator and inhibitor concentrations pH using new continuous enzyme assay with an automatic phosphate analyzer. The was shown to be the result tight binding two catalytically active enzyme-substrate complexes. reaction between is relatively slow, so that rate constants for release were derived from formation curves measured on time scale assays. pH-dependence in alkaline medium indicates both fluoride-enzyme interaction catalytic step are controlled same group protein. In acidic medium, considerably enhanced, presumably because protonation another group.