The Separation and Partial Characterization of L-Histidinol Phosphatase and an Alkaline Phosphatase of Saccharomyces cerevisiae

Two enzymes which effected the hydrolysis of the histidine biosynthetic intermediate histidinol phosphate were isolated from Saccharomyces cerevisiae. The enzymes were separated by diethylaminoethyl Sephadex column chromatography and partially characterized. The histidinol phosphatase was shown to be a specific enzyme, hydrolyzing only the histidine intermediate, histidinol phosphate. It was insensitive to inhibition by Be++ ions or EDTA. The alkaline phosphomonoesterase hydrolyzed a variety of phosphomonoesters, including histidinol phosphate. It was very sensitive to inhibition by Be++, and required Mg++ for maximal activity. A mutant lacking histidinol phosphatase was found to have the normal (wild type) level of the nonspecific alkaline phosphatase. The possibility that this enzyme can substitute for histidinol phosphatase under certain circumstances is discussed.