Monomeric alkaline phosphatase of Vibrio cholerae

Abstract

Alkaline phosphatase has been purified to homogeneity from two strains of Vibrio cholerae. The enzymes from both strains are single polypeptides of molecular weight 60,000. Both of the enzymes have pH optima around 8.0 and can act on a variety of organic phosphate esters, glucose-1-phosphate being the best substrate. The enzymes are unable to hydrolyze ATP and AMP. Although they have identical K_m values, the two enzymes differ significantly in V_max with p-nitrophenyl phosphate as substrate. The enzymes from the two strains also differ in their sensitivity to EDTA, P_i, and metal ions and activities of the apoenzymes. Ca²⁺ reactivated the apoenzymes most.