PURIFICATION AND CHARACTERIZATION OF AMINOPEPTIDASE YSPI FROM SCHIZOSACCHAROMYCES-POMBE

Aminopeptidase yspI was purified to apparent homogeneity from the fiss ion yeast Schizosaccharomyces pombe. The molecular mass of the native enzyme was estimated to be 184 kDa by gel filtration chromatography. A value of 92 kDa was calculated after sodium dodecyl sulfate-polyacryl amide gel electrophoresis. The enzyme is thus a dimer with two identic al subunits. Optimum pH for cleavage of synthetic aminoacyl-4-nitroani lides is 7.0. Mercury ions. EDTA and chloroquine were found to be pote nt inhibitors of aminopeptidase yspI activity. Substrate specificity s tudies indicate that the purified enzyme cleaves L-lysine-4-nitroanili de with high efficiency.