receptor-regulated binding of the labeled gtp analog , guanosine 5'-o- ( 3-thiotriphosphate ) ( [ 35s ] gtp [ s ] ) , to guanine-nucleotide-binding proteins ( g-proteins ) was studied in porcine atrial membranes enriched in muscarinic acetylcholine ( mach ) receptors .
C0079469
guanosine
C0018353
gtp