Sequence of thirteen amino acids in the C-terminal end of bovine growth hormone and localization of a disulflde bridge

Abstract

The carbamidomethyl derivative of reduced bovine growth hormone (BGH) was extensively attacked by carboxypeptidases A and B, and approximately 19 moles of various amino acids was liberated. The correct sequence of 13 amino acids could be established by selective cleavage of the methionyl bonds in the molecule and isolation of a C-terminal dodecapeptide by filtration through Sephadex G-25. The structure of this peptide was studied by carboxypeptidase A attack, Edman degradation, and further study of the fragments obtained by chymotryptic digestion. A disulfide bond connecting the two half-cystines in the dodecapeptide was discovered by the comparative study of the peptides released by the action of cyanogen bromide on native or reduced and blocked hormone. The structure of the C-terminal end in BGH is: ▪