[Studies on the pH-dependence, inhibition and reactivation of angiotension II-amide splitting enzymes in human erythrocytes (author's transl)].
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.
D002118:Calcium; D002729:Chloromercuribenzoates; D004492:Edetic Acid; D010450:Endopeptidases / Q000097:blood*; D004912:Erythrocytes / Q000201:enzymology*; D006801:Humans; D006863:Hydrogen-Ion Concentration; D007527:Isoenzymes / Q000097:blood; D007531:Isoflurophate / Q000494:pharmacology; D007700:Kinetics; D011480:Protease Inhibitors; D013347:Subcellular Fractions / Q000201:enzymology; D013696:Temperature
D002729:Chloromercuribenzoates; D007527:Isoenzymes; D011480:Protease Inhibitors; D007531:Isoflurophate; D004492:Edetic Acid; D010450:Endopeptidases; D002118:Calcium
Untersuchungen über die pH-Abhängigkeit, Hemmbarkeit und Reaktivierbarkeit von Angiotensin II-amid-spaltenden Aminopeptidasen menschlicher Erythrozyten