title: Aminopeptidase P from rat brain. Purification and action on bioactive peptides.
abstract: Aminopeptidase P (EC 3.4.11.9) was purified from rat brain cytosol. A subunit Mr of 71,000 was determined for the reduced, denaturated protein whereas an Mr of 143,000 was determined for the native enzyme. The purified aminopeptidase P selectively liberated all unblocked, preferentially basic or hydrophobic ultimate amino acids from di-, tri- and oligopeptides with N-terminal Xaa-Pro- sequences. Corresponding peptides with penultimate Ala instead of Pro were cleaved with much lower rates; oligopeptides with residues other than Pro or Ala in the penultimate position appeared not to be substrates for the enzyme. Several bioactive peptides with Xaa-Pro sequences, especially bradykinin, substance P, corticortropin-like intermediate lobe peptide, casomorphin and [Tyr]melanostatin were shortened by the N-terminal amino acid by aminopeptidase P action. Rat brain aminopeptidase P was optimally active at pH 7.6-8.0 in the presence of Mn2+. Chelating agents and SH-reacting reagents inhibited the enzyme, but common inhibitors of aminopeptidases, like amastatin or bestatin, of prolidase or of dipeptidyl peptidases II and IV, like N-benzoyloxycarbonyl-proline or epsilon-benzyl-oxycarbonyl-lysyl-proline, as well as antibiotics like beta-lactam ones, bacitracin or puromycin, had little or no effect.
authors.affiliation: Anatomisches Institut der Universität Kiel, Federal Republic of Germany.
authors.forename: H T
authors.initials: HT
authors.lastname: Harbeck
authors.forename: R
authors.initials: R
authors.lastname: Mentlein
mesh_terms: D000595:Amino Acid Sequence; D000626:Aminopeptidases / Q000302:isolation & purification* / Q000378:metabolism; D000818:Animals; D001921:Brain / Q000201:enzymology*; D002845:Chromatography / Q000379:methods; D002850:Chromatography, Gel / Q000379:methods; D002852:Chromatography, Ion Exchange / Q000379:methods; D003600:Cytosol / Q000201:enzymology; D017886:Durapatite; D004789:Enzyme Activation; D004795:Enzyme Stability; D006728:Hormones / Q000378:metabolism; D006882:Hydroxyapatites; D007700:Kinetics; D046911:Macromolecular Substances; D008969:Molecular Sequence Data; D011480:Protease Inhibitors / Q000494:pharmacology; D051381:Rats; D011919:Rats, Inbred Strains; D013379:Substrate Specificity; D013816:Thermodynamics
chemical_list: D006728:Hormones; D006882:Hydroxyapatites; D046911:Macromolecular Substances; D011480:Protease Inhibitors; D017886:Durapatite; D000626:Aminopeptidases; C022750:X-Pro aminopeptidase