A New Kinetic Method for Assaying Serum 5′-Nucleotidase Using Nucleoside Oxidase

Abstract

A sensitive kinetic determination of serum 5′-nucleotidase activity is described. Nucleoside oxidase catalyzes the oxidative coupling reaction of phenolic compounds and 4-aminoantipyrine to form colored substances in proportion of the amount of nucleoside. The present method relies on this phenomenon. Human serum 5′-nucleotidase was assayed using 5′-AMP as a substrate. When adenosine liberated was oxidized by nucleoside oxidase in the presence of phenolic compounds and 4-aminoantipyrine, a colored substance was formed at the same time. The rate of colored substance formation was proportional to the 5′-nucleotidase activity. The proposed method shows a low variation and a good correlation with the reference method. 3′-Nucleotidase was also assayed in a similar manner.