[Studies on the pH-dependence, inhibition and reactivation of angiotension II-amide splitting enzymes in human erythrocytes (author's transl)].
Res Exp Med (Berl), 1976/8/25;168(2):89-100.
Nast HP, Distler A, Müller D, Kantarcioglu G, Walter U, Wolff HP
PMID: 10611
Abstract
Aminopeptidase activity of three fractions of human erythrocytes (membranes free of hemoglobin; hemolysate free of membranes; enzyme protein fraction made free of hemoglobin by DEAE-cellulose) was measured by a NADH dependent optical test using asparaginyl1-angiotension II-amide as substrate. 1. From the enzyme protein fraction 6 subfractions were obtained by (NH4)2SO4 precipitation. By measuring enzyme kinetics at three different pH-values (pH 5,0; 7,0; 8,0) with and without addition of the effectors Na2EDTA and Ca++ the existence of 6 different enzymes could be demonstrated. 2. The aminopeptidase activity of the hemolysate made free of membranes could be inhibited by diisopropylfluorphosphate and p-chloromercuribenzoate at three different pH-values (pH 5,0; 6,5; 7,0; 8,0 and 6,5; 7,0; 8,0 respectively). 3. A reduction of enzymatic activity of 20% was found after incubation at 37degreesC for two hours.
MeSH terms
Calcium; Chloromercuribenzoates; Edetic Acid; Endopeptidases; Erythrocytes; Humans; Hydrogen-Ion Concentration; Isoenzymes; Isoflurophate; Kinetics; Protease Inhibitors; Subcellular Fractions; Temperature
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