Recombination of the biologically active peptides from a tryptic digest of bovine growth hormone.

Two bovine growth hormone peptides containing residues 96 to 133 in one and a larger peptide corresponding to residues 1 to 95 and 151 to 191 linked by a disulfide bond have been recombined. Recombination was performed in 1.0 N acetic acid without and with 8 M urea and the recombined peptides were purified by gel filtration. Evidence of recombination of the peptides has been established by gel filtration, polyacrylamide gel disc electrophoresis, amino acid composition, ultraviolet absorption, circular dichroism, and intrinsic fluorescence. The molar growth promoting activity of the recombined peptides measured by tibial width assay in hypophysectomized rats was 10% that of the native hormone and greater than the sum (1%) of the growth promoting activities of the individual peptides. These studies suggest that some contribution of the larger peptide is necessary for more complete expression of the growth promoting activity of the bovine growth peptide corresponding to residues 96 to 133.