Isolation and characterization of a thermostable aminopeptidase(aminopeptidase T) from Thermus aquaticus YT-1, an extremely thermophilic bacterium.

Abstract

A thermostable aminopeptidase, called aminopeptidase T, from the extract of Thermus aquaticus YT-1 was purified and characterized. The enzyme had a dimeric structure, its relative molecular mass being 108, 000 by gel filtration, and 48, 000 by SDS-PAGE. The optimum pH of the enzyme activity was in the range of 8.5 to 9.0. The enzyme was significantly thermostable as it still retained 60% of its original activity even after heat treatment for 20 hr at 80°C. The enzyme activity was inhibited by metal-chelating agents. The enzyme had a low substrate specificity.