Inorganic pyrophosphatase activity of purified bovine pulp alkaline phosphatase at physiological pH

At physiological pH, the hydrolytic activity of purified bovine pulp alkaline phosphatase toward phosphorus compounds was observed to be in the order of inorganic pyrophosphate greater than beta-glycerophosphate greater than phosphorylcholine greater than p-nitrophenylphosphate greater than glucose-6-phosphate. Optimum pH of the enzyme toward inorganic pyrophosphate was shown to be 8.5, with around 60% of the activity at pH 7.5. The activity was increased by the addition of Mg2+, but a different pattern of activation was observed between pH 7.5 and 8.5.