Human Somatotropin:

The amino terminal 54 residue peptide fragment of human somatotropin, [Cys(Cam)53]‐HGH‐(I‐54), has been synthesized by the solid‐phase method. The symmetrical anhydride and active ester coupling methods were used exclusively. The synthetic product was purified by gel filtration, isoelectric focusing, and partition chromatography. It was found to be homogeneous by six additional criteria. In complement fixation experiments the synthetic product was immunologically active with antisera to HGH and [Cys(Cam)53]‐HGH‐(I‐134). Antiserum raised against the synthetic product was immunologically active in the homologous assay and with HGH, [Cys(Cam)53]‐HGH‐(I‐134), and [Cys(Cam)53]‐HGH‐(15–125). The synthetic fragment exhibited 53% of the activity of [Cys(Cam)53]‐HGH‐(I‐134) in the rat tibia assay.