Biomaterial Database

Relaxin: a disulfide homolog of insulin. 1977

C Schwabe, and J K McDonald

Relaxin, a peptide hormone responsible for the widening of the birth canal in mammals, has been purified from the ovaries of pregnant hogs. The amino acid sequences of its constituent A and B chains were determined, and the positions of the disulfide cross-links were established. Relaxin was shown to be identical to insulin with respect to its disulfide bond distribution, but significant homology was lacking in other positions. These findings suggest that relaxin and insulin were derived from a common ancestral gene. Since the intrauterine mode of propagation is synonymous with the development of mammals, the genetic distance between insulin and relaxin should therefore permit an estimate of the earliest possible time of commitment of one evolutionary branch to the development of mammals. This event was estimated to have occurred about 5 X 10(8) years ago.

UI	MeSH Term	Description	Entries
D007328	Insulin	A 51-amino acid pancreatic hormone that plays a major role in the regulation of glucose metabolism, directly by suppressing endogenous glucose production (GLYCOGENOLYSIS; GLUCONEOGENESIS) and indirectly by suppressing GLUCAGON secretion and LIPOLYSIS. Native insulin is a globular protein comprised of a zinc-coordinated hexamer. Each insulin monomer containing two chains, A (21 residues) and B (30 residues), linked by two disulfide bonds. Insulin is used as a drug to control insulin-dependent diabetes mellitus (DIABETES MELLITUS, TYPE 1).	Iletin,Insulin A Chain,Insulin B Chain,Insulin, Regular,Novolin,Sodium Insulin,Soluble Insulin,Chain, Insulin B,Insulin, Sodium,Insulin, Soluble,Regular Insulin
D010053	Ovary	The reproductive organ (GONADS) in female animals. In vertebrates, the ovary contains two functional parts: the OVARIAN FOLLICLE for the production of female germ cells (OOGENESIS); and the endocrine cells (GRANULOSA CELLS; THECA CELLS; and LUTEAL CELLS) for the production of ESTROGENS and PROGESTERONE.	Ovaries
D011247	Pregnancy	The status during which female mammals carry their developing young (EMBRYOS or FETUSES) in utero before birth, beginning from FERTILIZATION to BIRTH.	Gestation,Pregnancies
D011487	Protein Conformation	The characteristic 3-dimensional shape of a protein, including the secondary, supersecondary (motifs), tertiary (domains) and quaternary structure of the peptide chain. PROTEIN STRUCTURE, QUATERNARY describes the conformation assumed by multimeric proteins (aggregates of more than one polypeptide chain).	Conformation, Protein,Conformations, Protein,Protein Conformations
D012065	Relaxin	A water-soluble polypeptide (molecular weight approximately 8,000) extractable from the corpus luteum of pregnancy. It produces relaxation of the pubic symphysis and dilation of the uterine cervix in certain animal species. Its role in the human pregnant female is uncertain. (Dorland, 28th ed)	Relaxin B
D004220	Disulfides	Chemical groups containing the covalent disulfide bonds -S-S-. The sulfur atoms can be bound to inorganic or organic moieties.	Disulfide
D005075	Biological Evolution	The process of cumulative change over successive generations through which organisms acquire their distinguishing morphological and physiological characteristics.	Evolution, Biological
D005260	Female		Females
D005796	Genes	A category of nucleic acid sequences that function as units of heredity and which code for the basic instructions for the development, reproduction, and maintenance of organisms.	Cistron,Gene,Genetic Materials,Cistrons,Genetic Material,Material, Genetic,Materials, Genetic
D000595	Amino Acid Sequence	The order of amino acids as they occur in a polypeptide chain. This is referred to as the primary structure of proteins. It is of fundamental importance in determining PROTEIN CONFORMATION.	Protein Structure, Primary,Amino Acid Sequences,Sequence, Amino Acid,Sequences, Amino Acid,Primary Protein Structure,Primary Protein Structures,Protein Structures, Primary,Structure, Primary Protein,Structures, Primary Protein