STUDIES ON HUMAN SOMATOTROPIN. PREPARATION AND SOME PHYSICO-CHEMICAL PROPERTIES

A method for the preparation of human STH* was developed on the basis of Wilhelm's technique from 1961 which was simplified, by for example, introducing gel filtration. The purity of the preparation was established by a large number of purity criteria: zone electrophoresis on starch, zone electrophoresis in a density gradient, determination of N- and C-terminal end groups, determination of the N-terminal amino acid sequence, quantitative amino-acid analysis, determination of molecular weight by gel filtration (mol. wt.: 2.2×104), etc. Oxidation of human STH causes polymerization. The alteration of the degree of polymerization of the oxidized product was studied at varying pH levels. The molecular weight of the preparation at the highest degree of polymerization was found to be 45×104.