Pappalysin-1 (also known as pregnancy-associated plasma protein-A (PAPP-A); MERIOPS identifier M43.004) is a metalloendopeptidase that belongs to the MEROPS peptidase family M43B. It was first found in high concentrations in the blood of pregnant women. Later, it was identified as a proteinase responsible for cleavage of insulin-like growth factor binding protein (IGFBP)-4, an inhibitor of IGF action that mediates cell growth and survival signals. PAPP-A is expressed by different cell types, and thus no longer could be considered to be just "pregnancy-associated"[]. It is involved in rapid yet strictly controlled growth and development, including wound healing, bone remodelling, folliculogenesis, placental development, and atherosclerosis [].
