Recombinant Human ADAM12 Protein, CF

ADAM12, also known as meltrin-alpha, is a member of the ADAM family with metalloprotease activity (1). It consists of a propeptide, metalloproteinase, disintegrin, cysteine-rich, and EGF-like domains, a transmembrane segment, and a cytoplasmic tail with SH3 binding motifs. Human ADAM12 exists in two alternatively spliced forms: the prototype transmembrane form and a shorter secreted form lacking the transmembrane domain and the cytoplasmic tail. The secreted form has a 34 amino acid substitution in place of the transmembrane and cytoplasmic regions. In mouse, only the transmembrane form has been observed. The propeptide, which is cleaved in the Golgi by furin-like proprotein convertases, is retained in a noncovalent complex after ADAM12 secretion (2). Thus, the pro domain may function as an inhibitor of the proteolytic activity or play another unknown function. The known physiological substrates of ADAM12 are HBEGF in the heart (3) and IGFBP-3 and ‑5 in placental serum (4). Its proteolytic activity is inhibited by the tissue inhibitor of metalloproteinase-3 (Recombinant Human TIMP‑3, (Catalog # http://www.rndsystems.com/product_results.aspx?k=973-TM">973-TM) and alpha‑2‑macroglobulin. It also mediates cell-cell adhesion by interacting with integrins and syndecans as well as with additional unidentified molecules (4). ADAM12 may be a promising marker in prenatal diagnostics and breast cancer (5, 6). The recombinant ADAM12 contains the pro, metalloproteinase, and disintegrin domains. In addition to TIMP-3, the activity can also be inhibited by 5 mM 1,10-phenanthroline.