[Heme deficiency of soluble guanylate cyclase in rat platelets].
Analysis of soluble guanylate cyclase of rat platelets (105,000 g supernatant) revealed no activating effect of sodium nitroprusside on the enzyme activity. Dithiothreitol (2 x 10(-4) H) added to the sample stimulated the basal activity of guanylate cyclase in the presence of Mg2+ but did not induce the enzyme activation by sodium nitroprusside. Hemoglobin added to the enzyme did not influence its basal activity or the activating effect of sodium nitroprusside. DEAE-Cellulose chromatography of the 105,000 g supernatant revealed two protein peaks, I and II, of which only peak II possessed a guanylate cyclase activity. Fraction I added to a partly purified enzyme did not change the enzyme activity, nor did it enhance the sodium nitroprusside-induced activation of guanylate cyclase. Spectral analysis of the 105,000 g supernatant revealed that the presence of a maximum at 415-425 nm (Soret band) depended on the degree of plasma hemolysis. In the absence of hemolysis the Soret band was unobserved either in the 105,000 g supernatant or in fractions I and II. It is suggested that rat platelet guanylate cyclase is present in these cells in a heme-deficient state.
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D000818:Animals; D001792:Blood Platelets / Q000201:enzymology*; D002848:Chromatography, DEAE-Cellulose; D004229:Dithiothreitol / Q000737:chemistry; D004789:Enzyme Activation; D006162:Guanylate Cyclase / Q000378:metabolism*; D006418:Heme / Q000172:deficiency*; D006454:Hemoglobins / Q000737:chemistry; D008297:Male; D009599:Nitroprusside; D051381:Rats; D012995:Solubility; D013057:Spectrum Analysis
D006454:Hemoglobins; D009599:Nitroprusside; D006418:Heme; D006162:Guanylate Cyclase; D004229:Dithiothreitol
Gemdefitsitnost' rastvorimoĭ guanilattsiklazy trombotsitov krysy.