The metalloproteinase pregnancy-associated plasma pro-tein-A (PAPP-A) cleaves a subset of insulin-like growth factor binding proteins (IGFBP), which inhibit the activities of insulin-like growth factor (IGF). Through this proteolytic activity, PAPP-A is believed to regulate IGF bioavailability in several biological systems, including the human repro-ductive system and the cardiovascular system. PAPP-A adheres to mammalian cells by interactions with glycos-aminoglycan (GAG), thus targeting the proteolytic activity of PAPP-A to the cell surface. .
