[Isolation and molecular kinetic properties of the angiotensin-converting enzyme from the human heart].
An angiotensin-converting enzyme was isolated from human heart using N[-1(S)-carboxy-5-aminopentyl]glycyl-glycine as an affinity adsorbent. The isolation procedure resulted in an enzyme purified 1650-fold. The enzyme specific activity was 38.0 u./mg protein, Mr = 150 kD. The pH optimum for the angiotensin-converting enzyme towards Hip-His-Leu lies at 7.8, Km = 1.2 mM. The enzyme was inhibited by the substrate (Ks' = 14 mM). The enzyme effectively catalyzed the hydrolysis of angiotensin I (Km = 10 microM; kcat = 250 s-1). NaCl, CaCl2 as well as Na2SO4 in the absence of Cl- activated the enzyme, whereas CH3COONa and NaNO3 did not influence the enzyme activity. It was found that the bradykinin-potentiating factor inhibited the cardiac angiotensin-converting enzyme with IC50 = 4.0 X 10(-8) M.
D000806:Angiotensin-Converting Enzyme Inhibitors; D002846:Chromatography, Affinity; D006801:Humans; D006868:Hydrolysis; D007700:Kinetics; D008970:Molecular Weight; D009206:Myocardium / Q000201:enzymology*; D007703:Peptidyl-Dipeptidase A / Q000302:isolation & purification* / Q000378:metabolism
D000806:Angiotensin-Converting Enzyme Inhibitors; D007703:Peptidyl-Dipeptidase A
Poluchenie i molekuliarno-kineticheskie svoĭstva angiotenzinprevrashchaiushchego fermenta iz serdtsa cheloveka.