title: Characterization of two thiol-dependent aminopeptidases partially purified from human placenta.
abstract: 1. Two thiol-dependent aminopeptidases (I and III) were partially purified from the soluble fraction of human placenta. 2. Aminopeptidase I preferred L-alanine-beta-naphthylamide (AlaNA) as substrate at pH 7.0-7.5. It was sensitive to heat and some divalent metal ions (Co2+, Ni2+, Zn2+) but resistant to EDTA, and some amino acids. 3. Aminopeptidase III hydrolysed equally well AlaNA and ArgNA at pH 6.5-7.0. It was markedly suppressed by EDTA and reactivated by Co2+. It was inhibited by heat, some amino acids, benzamadine and puromycin.
mesh_terms: D000626:Aminopeptidases / Q000037:antagonists & inhibitors / Q000145:classification / Q000302:isolation & purification*; D004789:Enzyme Activation / Q000187:drug effects; D005260:Female; D006801:Humans; D006868:Hydrolysis; D010920:Placenta / Q000201:enzymology*; D011247:Pregnancy; D013379:Substrate Specificity; D013438:Sulfhydryl Compounds / Q000494:pharmacology*; D013696:Temperature
chemical_list: D013438:Sulfhydryl Compounds; D000626:Aminopeptidases