A unified assay for six enzymes of glutamate metabolism

Abstract

A single assay system has been developed for six enzymes of glutamate metabolism: glutamate dehydrogenase, glutaminase, asparate aminotransferase, γ-aminobutyrate aminotransferase, alanine aminotransferase, and glutamate decarboxylase. The first five are assayed by coupling them to Escherichia coli glutamate decarboxylase and measuring the release of 14CO2 from radioactive substrates. Glutamate decarboxylase is assayed directly. The assays are simple, use but one technique, and require very little working time. At a reasonable cost per assay, they are considerably more sensitive than other commonly used assays for the same enzymes. The sensitivity of the assay at a fixed price increases as the substrate concentration decreases. © 1979.