Disulfide bonds in native and recombinant fish growth hormones.

Disulfide linkages were characterized for the first time in a fish growth hormone. Trypsin digestion of chum salmon growth hormone, followed by mass spectrometry established that Cys-49 is linked to Cys-161, while Cys-178 is linked to Cys-186. This is analogous to the big loop, little loop pattern found in human growth hormone. Ninety-three percent of the primary structure of a recombinant rainbow trout growth hormone whose cDNA codes for the same amino acid sequence as chum salmon growth hormone was confirmed by mass spectrometric peptide mapping.