Modification of bovine somatotropin (growth hormone) with plasmin

Autor: Michael Wallis, Teresa K. Surowy
Rok vydání: 1983
Předmět:
Zdroj: Journal of Protein Chemistry. 2:347-362
ISSN: 1573-4943
0277-8033
DOI: 10.1007/bf01025234
Popis: Although much work has been reported on modification of human somatotropin with plasmin and has revealed important information about structure-function relationships, plasmin modification of nonprimate somatotropins (which differ markedly in structure and biological actions from the human hormone) has been little studied. Therefore we investigated plasmin digestion of bovine somatotropin. Digestion was less rapid but more extensive than that of human somatotropin. Structural characterization of digestion products resolved by gel filtration suggested that a major product after 24 h was a disulfide-linked fragment comprising residues 1–133 plus 140–177. Further cleavage products were found in aggregated material and minor fractions. In radioimmunoassay for bovine somatotropin, activity was retained only by the unfractionated digest and aggregated material. In radioreceptor assay for somatotropin using receptors from livers of late-pregnant rabbit all preparations retained some activity. The results suggest that receptor- and antibody-binding sites in bovine somatotropin are not identical and that greater activity may result from specific association of fragments that are less active or inactive once separated.
Databáze: OpenAIRE
Externí odkaz: