title: The relaxin peptide family--structure, function and clinical applications.
abstract: The relaxin peptide family in humans consists of seven members, relaxin-1, -2 and -3 and insulin-like (INSL) peptides 3, 4, 5 and 6. It is an offshoot of the large insulin superfamily. Each member consists of two chains, commonly referred to as A and B, which are held together by two inter-chain disulfide bonds and another intra-chain disulfide bond present within the A chain. The cysteine residues present in each chain, together with the distinctive disulfide bonding pattern, are conserved across all members of the superfamily. The chemical synthesis of these complex peptides poses a significant challenge. In the past, random combination of the two synthetic S-reduced chains under oxidizing conditions was utilized to form the three disulfide bonds. Nowadays, with the aid of highly efficient solid phase peptide synthesis methodologies, in conjunction with selective S-thiol-protecting groups, combination of individual A- and B- chains by sequential chemical formation of each of the three disulfide bonds is now possible resulting in good yields of these peptides. The relaxin peptide family members bind to G-protein coupled receptors (GPCRs) which have been classified as relaxin family peptide (RXFP) receptors. The various unique receptor-ligand interactions are outlined in this review, together with the physiological roles of the relaxin peptide family members and lastly their past and present clinical applications.
authors.affiliation: Florey Neuroscience Institutes, The University of Melbourne, Victoria, Australia.
authors.forename: Linda Jiaying
authors.initials: LJ
authors.lastname: Chan
authors.forename: Mohammed Akhter
authors.initials: MA
authors.lastname: Hossain
authors.forename: Chrishan S
authors.initials: CS
authors.lastname: Samuel
authors.forename: Frances
authors.initials: F
authors.lastname: Separovic
authors.forename: John D
authors.initials: JD
authors.lastname: Wade
mesh_terms: D000595:Amino Acid Sequence; D000818:Animals; D006801:Humans; D008969:Molecular Sequence Data; D043562:Receptors, G-Protein-Coupled / Q000378:metabolism; D018000:Receptors, Peptide / Q000378:metabolism; D012065:Relaxin / Q000138:chemical synthesis / Q000737:chemistry / Q000378:metabolism* / Q000627:therapeutic use*
chemical_list: D043562:Receptors, G-Protein-Coupled; D018000:Receptors, Peptide; C033395:relaxin receptors; D012065:Relaxin