In previous work, we demonstrated that monomeric human GH (hGH) digested with thrombin can be resolved after reduction and S-carbamidomethylation into two peptides, one comprising residues 1–134 (here designated 1–134T) and the carboxyl-terminal peptide 135–191 (designated 135–191T). In the present study, the noncovalent recombination of these peptides is described. S-carbamidomethylated peptides 1–134 (1–134C) and 141–191 (141–191C) have also been prepared from a more acidic form of hGH (C-type) isolated during the preparation of hGH monomer by chromatography on diethylaminoethyl-cellulose. The recombination of these peptides has also been studied. Finally, peptide 42–134 has been produced by digestion of peptide 1–134T with human plasmin. Various attempts to recombine this peptide with peptides 135–191T or 141–191C were unsuccessful. Noncovalent recombination of the peptides was achieved by dissolving equimolar amounts of the materials in 0.5% ammonium bicarbonate solution containing 6 M guanidine-HCl o...