[A0-phenylalanyl] relaxin (porcine): an active intermediate.

A [phenylalanylA0] relaxin has been isolated as a byproduct during large scale porcine relaxin preparations, using ion exchange chromatography on CM-cellulose at pH 7.8 followed by high performance liquid chromatography on reversed phase columns. The elongation at the N terminus of the A-chain has been demonstrated by amino acid and sequence analyses of the isolated and carboxymethylated relaxin-A-chain. The phenylalanyl relaxin and B29 relaxin are indistinguishable by circular dichroism spectroscopy, in mouse pubic ligament assay, and radioimmunoassay. The occurrence of phenylalanyl relaxin may be caused by an incomplete conversion of prorelaxin to relaxin.