Catalytic Ability of Alkaline Phosphatase to Promote P-O-P Bond Hydrolyses of Inorganic Diphosphate and Triphosphate

Alkaline phosphatase(EC3.1.3.1) catalyzed the hydrolyses of inorganic diphosphate(pyrophosphate) and triphosphate. The rate of P-O-P bond cleavage decreased with increasing pH at alkaline region, in contrast to the pH-dependencies of P-O-C and P-F bond cleavages. The enzyme was inactive toward cyclic triphosphate and, unlike well-known inorganic pyrophosphatase(EC3.6.1.1), was not inhibited by fluoride ion.