Biosynthesis of endothelium-derived relaxing factor: a cytosolic enzyme in porcine aortic endothelial cells Ca2+-dependently converts L-arginine into an activator of soluble guanylyl cyclase.
In the presence of porcine aortic endothelial cytosol, soluble guanylyl cyclase purified from bovine lung was activated by L-arginine up to 2.5-fold, with an EC50 of about 6 microM. This activation was dependent on NADPH and Ca2+. The EC50 for Ca2+ was about 60 nM. No effect of L-arginine on guanylyl cyclase was observed when the cytosolic proteins were heat-denaturated. The effect of L-arginine was inhibited by NG-monomethyl-L-arginine and hemoglobin. These results indicate that endothelial cells contain a cytosolic enzyme which is directly or indirectly regulated by Ca2+ and converts L-arginine into a compound which in stimulating soluble guanylyl cyclase behaves similar to endothelium-derived relaxing factor.
Mayer
B
B
Institut für Pharmakologie, Freie Universität Berlin, F.R.G.
Schmidt
K
K
Humbert
P
P
Böhme
E
E
D000818:Animals; D001011:Aorta; D001120:Arginine / Q000378:metabolism / Q000494:pharmacology*; D002118:Calcium / Q000494:pharmacology*; D002417:Cattle; D002478:Cells, Cultured; D003600:Cytosol / Q000201:enzymology; D004730:Endothelium, Vascular / Q000201:enzymology*; D004789:Enzyme Activation; D006162:Guanylate Cyclase / Q000378:metabolism*; D007700:Kinetics; D008168:Lung / Q000201:enzymology; D009569:Nitric Oxide / Q000096:biosynthesis*; D013552:Swine
D009569:Nitric Oxide; D001120:Arginine; D006162:Guanylate Cyclase; D002118:Calcium