[Physico-chemical properties of alkaline phosphatase from the seal small intestine].

Alkaline phosphatase of the Greenland seal was purified to homogeneity, using immobilized concanavalin A. The specific activity of the enzyme is 1200-1500 mu/mg protein. The molecular mass of alkaline phosphatase as determined by electrophoresis performed under non-denaturating conditions is 260 kD, whereas that determined in the presence of beta-mercaptoethanol and SDS is 70 kD, which points to the tetrameric type of the seal alkaline phosphatase molecule. Using the atomic adsorption method, it was demonstrated that the phosphatase molecule contains four zinc atoms. Some physico-chemical parameters of seal alkaline phosphatase (pH-dependence, effects of temperature and cations on the enzyme activity, pI, thermal stability) were determined.