Isolation and Characterization of Fragments of Reduced andS-Carbamidomethylated Human Growth Hormone Produced by Plasmin Digestion. II. Biological and Immunological ActivitiesEndocrinology102:*

Abstract

Noncovalent complexes of peptide fragments, as well as individual fragments, isolated from digests of reduced and S-carbamidomethylated human GH (hGH) produced with human plasmin have been studied for biological and immunological activity. Noncovalent complexes of peptide 1–134 and peptide 141–191 and a complex containing approximately equal proportions of peptide 1–134 and peptide 42–134 bound to peptide 141–191 were found to retain 50–100% of the ability of hGH a) to promote growth and stimulate cartilage metabolism when injected into hypophysectomized rats, b) to induce iV-acetyllactosamine synthetase in mammary tissue explants from pregnant mice, and c) to stimulate the in vitro oxidation of glucose by isolated adipose tissue from hypophysectomized rats. In contrast to previous findings with covalent complexes containing peptide 1–134, the noncovalent complexes showed only 20–50% of the insulin-like activity of native hGH. The noncovalent complex, 1–134:141–191, exhibited more than twice the lactogeni...