Degradation of Nucleoside Diphosphate Sugars by Human and Rat Serum. Properties of the Serum Nucleotide Pyrophosphatases

Abstract

Publisher Summary This chapter describes the properties of the serum nucleotide pyrophosphatases and degradation of nucleoside diphosphate sugars by human and rat serum. It states that the nucleoside diphosphate sugars are decomposed in three different ways: (1) by a transfer reaction, (2) by degradation of the glycosylnucleotides by nucleotide pyrophosphates, and (3) by chemical decomposition of the glycosylnucleotides. The chapter also discusses the competition between enzymic and chemical degradations of glycosylnucleotides and the properties of the nucleotide pyrophosphates from rat serum. To avoid erroneous interpretation of the glycosyltransferase activities in biological fluids, it is important to simultaneously determine the nucleotide pyrophosphatase and phosphatase activities and the chemical degradation of some of the glycosylnucleotides. In a study described in the chapter, the effect of Mn2+ on the decomposition of glycosylnucleotidesin human serum was that it did not stimulate the hydrolysis of all the tested glycosylnucleotides. Nucleotide pyrophosphatase and phosphatase activities were very high in rat serum.