Membrane proteins from rabbit and human platelets were separated by SDS/polyacrylamide-gel electrophoresis and the resolved polypeptides blotted on nitrocellulose. A family of GTP-binding proteins, termed Gn proteins, was detected by incubation of these blots with [alpha-32P]GTP in the presence of Mg2+. A major Gn protein with a molecular mass of 27 kDa (Gn27) and lesser amounts of 23, 24 and 25 kDa Gn proteins were observed in platelet membranes; much smaller amounts were in the platelet soluble fraction. Binding of [alpha-32P]GTP by platelet Gn proteins was blocked by GDP, GTP or guanosine 5′-[gamma-thio]triphosphate, but not by GMP or adenosine 5′-[beta gamma-imido]triphosphate. Rabbit and human red-cell membranes contained only Gn27. When rat tissues were analysed for Gn proteins, the largest amounts were found in brain, which contained two membrane-bound forms (Gn27 and Gn26) and a soluble form (Gn26).
Research Article| July 15 1987
Detection of 23-27 kDa GTP-binding proteins in platelets and other cells
R P Bhullar;
Biochem J (1987) 245 (2): 617–620.
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R P Bhullar, R J Haslam; Detection of 23-27 kDa GTP-binding proteins in platelets and other cells. Biochem J 15 July 1987; 245 (2): 617–620. doi: https://doi.org/10.1042/bj2450617
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