title: [Aminopeptidase activity in populations of human blood mononuclear cells].
abstract: The aminopeptidase N (AP N, EC 3.4.11.2) is an ectoenzyme of the plasma membrane, playing presumably an important role in the regulation of immunological processes. The specific activities of Ala-pNA and Leu-pNA cleavage (per cell) are distributed in monocytes T- and non-T-lymphocytes in a proportion of 1:0.2:0.25 and 1:0.17:0.18, respectively. The capacities of Ala-pNA and Leu-pNA hydrolysis in the total fraction T- and non-T-cells are distributed as 1:0.8 and 1:0.7, respectively. The main part of Ala-pNA cleavage was shown to be caused by AP N on the basis of the KM-value (0.5 mmol/l), the activation by CO2+ ions and the pH optimum (7.0-7.5). The Leu-pNA cleavage is dependent on CO2+ and DTT and distinct from the classical cytosolic leucyl aminopeptidase.
authors.affiliation: Forschungsabteilung Experimentelle Immunologie, Medizinischen Akademie Magdeburg.
authors.forename: D
authors.initials: D
authors.lastname: Kunz
authors.forename: E
authors.initials: E
authors.lastname: Schön
authors.forename: H J
authors.initials: HJ
authors.lastname: Hütter
authors.forename: S
authors.initials: S
authors.lastname: Ansorge
mesh_terms: D000626:Aminopeptidases / Q000097:blood / Q000378:metabolism*; D018826:CD13 Antigens; D004229:Dithiothreitol / Q000494:pharmacology; D004492:Edetic Acid / Q000494:pharmacology; D006801:Humans; D006863:Hydrogen-Ion Concentration; D007931:Leucyl Aminopeptidase / Q000097:blood; D007963:Leukocytes, Mononuclear / Q000201:enzymology*; D008670:Metals / Q000494:pharmacology; D008861:Microsomes / Q000201:enzymology; D012995:Solubility
chemical_list: D008670:Metals; D004492:Edetic Acid; D000626:Aminopeptidases; D007931:Leucyl Aminopeptidase; D018826:CD13 Antigens; D004229:Dithiothreitol