title: Subunit structured of pig small-intestinal brush-border aminopeptidase N.
abstract: Aminopeptidase N (EC 3.4.11.2), when isolated from pig intestine in either the proteinase- or detergent-released form, frequently appears to contain three polypeptide chains, here termed alpha, beta and gamma. We have established by an immunological technique that the beta- and gamma-polypeptides are derived from the alpha-chain and that the intact enzyme is a dimer, alpha 2. Each alpha-chain of the detergent form was shown to contain a hydrophobic anchor peptide about 35 amino acid residues in length, which included the N-terminal sequences. A peptide bond in the alpha-chain was very sensitive to proteolysis. Its cleavage generated the commonly observed forms: alpha beta gamma and beta 2 gamma 2. The gamma-fragment, which lacked the anchor peptide, was derived from the C-terminal part of the alpha-chain.
mesh_terms: D000596:Amino Acids / Q000032:analysis; D000626:Aminopeptidases; D000818:Animals; D018826:CD13 Antigens; D002850:Chromatography, Gel; D004591:Electrophoresis, Polyacrylamide Gel; D007421:Intestine, Small / Q000201:enzymology*; D008871:Microvilli / Q000201:enzymology; D008970:Molecular Weight; D010446:Peptide Fragments / Q000032:analysis; D013552:Swine
chemical_list: D000596:Amino Acids; D010446:Peptide Fragments; D000626:Aminopeptidases; D018826:CD13 Antigens