Identification of a dopamine-binding protein on the membrane of the human platelet.
The binding of [3H]dopamine to platelet membranes has been examined in an attempt to identify the putative dopamine-uptake mechanism of the platelet. [3H]Dopamine has been shown to bind to a 42,000 Da glycoprotein in platelet membrane with high affinity (Kd = 22.6 nM) and binding of [3H]dopamine was competed for by dopamine, molecules with catechol moieties, 5-hydroxytryptamine, GSH and ascorbic acid. Differences in pharmacological profile and molecular mass suggest that [3H]dopamine does not bind to a known receptor, a neuronal-type dopamine transporter or the platelet 5-hydroxytryptamine-uptake site. It is proposed that this novel binding site for dopamine, which has been purified 1000-fold from particulate platelet membrane, is likely to be a component of the dopamine-uptake mechanism of the human platelet.
Dean
B
B
Neurochemistry Unit Mental Health Research Institute of Victoria, Royal Park Hospital, Parkville, Vic. Australia.
McAdam
A J
AJ
Sundram
S
S
Pavey
G
G
Harrison
L C
LC
Copolov
D L
DL
D001692:Biological Transport; D001792:Blood Platelets / Q000378:metabolism*; D002462:Cell Membrane / Q000378:metabolism; D006801:Humans; D066298:In Vitro Techniques; D010980:Platelet Membrane Glycoproteins / Q000737:chemistry / Q000378:metabolism*; D011485:Protein Binding; D011954:Receptors, Dopamine / Q000502:physiology
D010980:Platelet Membrane Glycoproteins; D011954:Receptors, Dopamine