1 in homogenates of rat brain , the binding characteristics of tritiated opiates and opioid peptides were examined and the relative capacities of mu- , delta- and kappa-binding sites of the opiate receptor determined by saturation analysis.2 in competition experiments , binding of the selective mu-ligand [ ( 3 ) h ] - [ d-ala ( 2 ) , mephe ( 4 ) , gly-ol ( 5 ) ] enkephalin at the mu-site was displaced by [ d-ala ( 2 ) , d-leu ( 5 ) ] enkephalin with rather low affinity ( k ( i ) = 12.6 nm ) and more readily by the ketazocine-like compounds ( - ) -ethylketazocine ( k ( i ) = 3.1 nm ) and ( - ) -bremazocine ( k ( i ) = 0.32 nm ) , which also displaced the binding of [ ( 3 ) h ] - [ d-ala ( 2 ) , d-leu ( 5 ) ] enkephalin from the delta-site .
C0205753
opioid peptides
C0014298
enkephalin