Molecular target size analyses of the NMDA-receptor complex in rat cortex.
The molecular weights of different subunits of the NMDA-receptor complex were determined by high-energy radiation inactivation analyses of the binding of [3H]L-glutamate, [3H](3-(+/-)-2-(carboxypiperazin-4-yl)propyl-1-phosphonic acid (CPP), [3H]N-(1-[2-thienyl]cyclohexyl)3,4-piperidine (TCP) and [3H]glycine to rat cortical membranes. The molecular target sizes of [3H]L-glutamate binding (the recognition site), [3H]TCP binding (the ionophore) and [3H]glycine (a modulatory unit) were similar: 121,000, 118,000 and 115,000 Da, respectively. These results suggest that the three subunits are on the same protein. The molecular weight of [3H]CPP binding was 209,000 Da. This suggests that in order to bind [3H]CPP (a competitive antagonist) with high affinity an additional macromolecule may be associated to the agonist site.
Honoré
T
T
Ferrosan Research Division, Soeborg, Denmark.
Drejer
J
J
Nielsen
E O
EO
Watkins
J C
JC
Olverman
H J
HJ
Nielsen
M
M
D000818:Animals; D002540:Cerebral Cortex / Q000032:analysis*; D005615:Freezing; D005971:Glutamates / Q000378:metabolism; D005998:Glycine / Q000378:metabolism; D066298:In Vitro Techniques; D008566:Membranes / Q000187:drug effects / Q000378:metabolism; D008970:Molecular Weight; D010622:Phencyclidine / Q000031:analogs & derivatives / Q000378:metabolism; D010879:Piperazines / Q000378:metabolism; D051381:Rats; D016194:Receptors, N-Methyl-D-Aspartate; D017981:Receptors, Neurotransmitter / Q000032:analysis* / Q000378:metabolism
D005971:Glutamates; D010879:Piperazines; D016194:Receptors, N-Methyl-D-Aspartate; D017981:Receptors, Neurotransmitter; C012058:tenocyclidine; D010622:Phencyclidine; C015068:1-(3-chlorophenyl)piperazine; D005998:Glycine