Amino Acid Sequence of a Biologically Active Fragment of Bovine Growth Hormone

Abstract The amino acid sequence of a biologically active fragment, A-II, isolated from a fraction of a tryptic digest of bovine growth hormone which has metabolic activity in humans similar to human growth hormone has been determined. The 37 amino acid peptide was cleaved with cyanogen bromide at its single methionine residue to yield two fragments. The larger fragment corresponded to the NH2-terminal and the smaller peptide (nine amino acids) to the COOH-terminal region. The sequence of 37 amino acids was established by analysis of cyanogen bromide fragments, chymotryptic and tryptic peptides. Good homology was found in the sequence between the bovine growth hormone fragment and peptides occurring in human growth hormone and human chorionic somatomammotropin. This suggests that there may be a common active site in growth hormone of various species.