Metabolic studies with 65Zn. X. Biosynthesis of alkaline phosphatase in cultures of Pseudomonas fluorescens.

Alkaline phosphatase from Pseudomonas fluorescens has been partially purified. Labelled 65ZnCl2 in the culture medium is incorporated in the most purified preparations. The enzyme shows a pH optimum of 7.2-7.5 and a Km value for p-nitrophenyl phosphate of 1 times 10(-4). Zinc ions at high concentration inhibit enzyme activity. The protective effect of Mg on the inactivation of alkaline phosphatase by heat is also reported.