An endogenous regulator of the guanylate cyclase activity of human platelets

Chromatography of soluble human platelet guanylate cyclase (105,000 g supernatant) on DEAE-cellulose in a linear gradient of NaCl (0-0.5 M) in 50 mM Tris-HCl buffer pH 7.6 gave two protein peaks, I and II, of which only peak II possessed the guanylate cyclase activity (0.18-0.22 M NaCl). The protein...

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Bibliographic Details
Published in:	Biokhimiia (Moscow, Russia) Vol. 55; no. 10; p. 1812
Main Authors:	Busygina, O G, Severina, I S
Format:	Journal Article
Language:	Russian
Published:	Russia (Federation) 01-10-1990
Subjects:	Blood Platelets - enzymology Chromatography, DEAE-Cellulose Guanylate Cyclase - antagonists & inhibitors Guanylate Cyclase - blood Hemeproteins - isolation & purification Humans Nitroprusside
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Summary:	Chromatography of soluble human platelet guanylate cyclase (105,000 g supernatant) on DEAE-cellulose in a linear gradient of NaCl (0-0.5 M) in 50 mM Tris-HCl buffer pH 7.6 gave two protein peaks, I and II, of which only peak II possessed the guanylate cyclase activity (0.18-0.22 M NaCl). The protein fraction I was found to possess an inhibiting activity; its addition to the partially purified enzyme decreased the guanylate cyclase activity by 60-70% in the presence of Mg2+ with no effect on the enzyme activity in the presence of Mn2+. The isolated enzyme lost (by approximately 80%) its ability to be activated by sodium nitroprusside; the latter was reconstituted after addition of the inhibiting fraction. The data obtained testify to the heme origin of the endogenous inhibitor of human platelet guanylate cyclase.
ISSN:	0320-9725