HUMAN SOMATOTROPIN .58. SEMISYNTHESIS OF HUMAN SOMATOTROPIN ANALOGS

Complementation of the natural NH2-terminal 134-amino acid fragment of the reduced, carbamoylmethylated human somatotropin with synthetic analogs of COOH-terminal fragments of 57, 42, or 38 amino acids of reduced, carbamoylmethylated human somatotropin has been investigated. It was found that synthetic fragments of 57 and 42 amino acids gave recombinants with full growth-promoting activity, whereas attempts to obtain a recombinant with the synthetic 38-amino acid fragment were unsuccessful. The synthesis of two analogs of the COOH-terminal fragment of human somatotropin, human [Nle170, Ala165,182,189] somatotropin-(150-191) and human [Nle170, Ala165,182,189]somatotropin-(154-191), is herein described.