632. Reactivation of milk phosphatase following heat treatment: IV. The influence of certain metallic ions

Abstract

1. Reactivation of alkaline milk phosphatase is affected by the presence of ions, Mg 2+ , Zn 2+ and Mn 2+ being activating and Cu 2+ , Ni 2+ and Co 2+ being inhibitory. 2. Cu 2+ will inhibit reactivation induced by Mg 2+ , but has no effect upon Zn 2+ -induced reactivation. 3. Using washed cream, either alone or in admixture with boiled whey treated with cationic resin, reactivation occurs in the presence of added Mg 2+ , but not when Zn 2+ is added. 4. Experiments with EDTA. confirm that metallic ions play a part both in alkaline phosphatase activity and in reactivation. 5. It is suggested that either Mg 2+ or Zn 2+ or both play a part in reactivation.