Human somatotropin: covalent reconstitution of two polypeptide contiguous fragments with thrombin

Thrombin has been shown to resynthesize the Arg134-Thr135 peptide bond between the 134- and 57-residue thrombin fragments of reduced and carbamidomethylated human somatotropin at pH 6.0 in 90% (vol/vol) glycerol. The maximal amount of synthesis was about 20% as estimated by sodium dodecyl sulfate gel electrophoresis and radioreceptor assay. The resynthesized polypeptide was isolated and shown to be indistinguishable from the reduced and carbamidomethylated hormone when tested by two receptor-binding assays, radioimmunoassay, and rat tibia test.