The sites of high affinity binding of L-[3H]glutamic acid in human platelets. a new type of platelet receptor?
Almazov, V.A.; Popov, I.G.; Gorodinskiĭ, A.I.; Mikhaĭlova, I.A.; Dambinova, S.A.
Biokhimiia 53(5): 848-852
1988
ISSN/ISBN: 0320-9725 PMID: 2901864 Document Number: 311662
The total membrane fraction of human platelets was found to contain high affinity sites of L-[3H]glutamic acid binding (Kd = 100 nM, Bmax = 1.06 pmol/mg protein). The pH optimum for binding is at pH approximately 6.9 Na+ (1-150 mM) inhibit glutamate binding by platelet membranes (IC50 = 12 mM). Ca2+ (50-100 microM) stimulate the binding by 10-20% and inhibit it by 20-30% at concentrations of 1-5 mM. Monoclonal antibodies to the glutamate receptor strongly suppress the L-[3H]glutamate binding by platelet membranes (IC50 = 300 nm). The presence in human platelets of a glutamate-sensitive receptor complex similar to the central nervous system glutamate receptor is postulated.