A process for producing an insulin type peptide, for example a relaxin, involving oxidizing a methionine residue on a B-chain having cysteine residues and combining the B chain with an A chain having cysteine residues to form a peptide having intermolecular disulphide links and biological activity. Novel synthetic relaxin 1 and methionine oxidized relaxins and Met(O) B-chains having enhanced solubility are disclosed.
