title: Effect of carnosine on the activation of human platelet soluble guanylate cyclase by sodium nitroprusside and protoporphyrin IX.
abstract: Effect of carnosine on the activation of soluble guanylate cyclase by sodium nitroprusside and protoporphyrin IX was studied using human platelet 105000 g supernatants and partially purified heme-deficient guanylate cyclase preparations. In experiments with 105000 g supernatants, carnosine (1 mM) inhibited the enzyme activation by nitroprusside by about 70%. With the partially purified heme-deficient guanylate cyclase, the enzyme activation by nitroprusside was lowered by 86%, and the remaining insignificant stimulatory effect remained unchanged upon carnosine addition. The stimulatory effect of protoporphyrin IX on the partially purified heme-deficient enzyme preparation did not differ from that observed with the 105000 g supernatant; carnosine addition had no effect on activation of guanylate cyclase by protoporphyrin IX. It was concluded that the inhibitory effect of carnosine on the ability of the enzyme to be activated by nitroprusside is due to the interaction of carnosine with guanylate cyclase, and that it is heme directed.
authors.affiliation: Institute of Biological and Medical Chemistry, USSR Academy of Medical Sciences, Moscow.
authors.forename: I S
authors.initials: IS
authors.lastname: Severina
authors.forename: O G
authors.initials: OG
authors.lastname: Busygina
mesh_terms: D001792:Blood Platelets / Q000201:enzymology*; D002336:Carnosine / Q000494:pharmacology*; D004347:Drug Interactions; D004789:Enzyme Activation / Q000187:drug effects; D005609:Free Radicals; D006162:Guanylate Cyclase / Q000097:blood / Q000187:drug effects*; D006801:Humans; D009599:Nitroprusside / Q000494:pharmacology*; D011524:Protoporphyrins / Q000494:pharmacology*; D012995:Solubility
chemical_list: D005609:Free Radicals; D011524:Protoporphyrins; D009599:Nitroprusside; D002336:Carnosine; C028025:protoporphyrin IX; D006162:Guanylate Cyclase