title: [Conditions of activation of guanylate cyclase from human platelets].
abstract: Preincubation (50 min, 0 degree C) with nitroprusside increases 12-fold the activity of human platelet guanylate cyclase. The stimulating effect of nitroprusside is enhanced two-fold by dithiothreitol (2 mM) and by 60% by hemoglobin (20 micrograms/ml). Storage of guanylate cyclase preparations (105000 g supernatant) for 2-3 days at 4 degrees C causes a progressive increase of the enzyme activity and diminishes the stimulating effect of nitroprusside. After storage of guanylate cyclase preparations for 3 days, hemoglobin (20 micrograms/ml) augments the stimulating effect of nitroprusside by 130%. It is concluded that the degree of activation of guanylate cyclase by nitroprusside reflects the functional state of the enzyme.
authors.forename: Iu Iu
authors.initials: IuIu
authors.lastname: Chirkov
authors.forename: I A
authors.initials: IA
authors.lastname: Tyshchuk
authors.forename: I S
authors.initials: IS
authors.lastname: Severina
mesh_terms: D001792:Blood Platelets / Q000201:enzymology*; D004229:Dithiothreitol / Q000494:pharmacology; D004789:Enzyme Activation; D004795:Enzyme Stability; D006162:Guanylate Cyclase / Q000037:antagonists & inhibitors / Q000097:blood / Q000378:metabolism*; D006801:Humans; D066298:In Vitro Techniques; D009599:Nitroprusside / Q000494:pharmacology
chemical_list: D009599:Nitroprusside; D006162:Guanylate Cyclase; D004229:Dithiothreitol
vernacular_title: Usloviia aktivatsii guanilattsiklazy trombotsitovv cheloveka.