Complaint
B7-33 is a singular chain peptide, a smaller analogous derivative of the endogenous relaxin protein (3). Typically, the relaxin peptide is composed of four components - a signal peptide, B chain, C chain, and COOH terminal. Several studies were conducted initially to replicate these peptide structures, however they resulted as being highly insoluble and inactive. After extensive research, scientists modified the structure by producing B chain and elongating the COOH terminal, thereby forming the first ever soluble analogue - B7-33 peptide - in 2016. (3)
Besides the structural difference, the peptide has some other variations from the endogenous proteins. B7-33 peptide has been suggested to act via pERK pathway instead of the cAMP pathway. H2-relaxin has been suggested to produce antifibrotic potential via cAMP pathway, which may potentially stimulate the formation of tumors in the body. This is a major side effect of the relaxin treatment. (1) Furthermore, the peptide may have a strong affinity towards the RXFP-1 receptors. The peptide appears to bind with these RXFP-1 receptors, stimulates pERK pathway, which then leads to increased synthesis of MMP-2 matrix metalloproteinase chemicals. These chemicals then inhibit the scarring of the tissues and thereby prevent fibrosis. (1)
