Inhibition of the action of pyrophosphatase and phosphatase on sugar nucleotides

Abstract

Sugar nucleotide degradation by Zn2+-requiring nucleotide pyrophosphatase and phosphatase was effectively inhibited by the addition of the chelator 2,3-dimercaptopropan-1-ol, along with low concentrations of nucleotides or their analogues. The addition of dimercaptopropanol alone completely inhibited alkaline phosphatase. This chelator has a much higher association constant for Zn2+ than for the Mn2+ needed for glycosyltransferase reactions, enabling selective chelation of Zn2+. Neither the chelator alone nor in combination with low concentrations of nucleotides was inhibitory to glycosyltransferase activities, as shown by xylosyltransferase in chick embryo epiphyseal microsomes and galactosyltransferase in rat serum.