the rank order for inhibition competition of [ 3h ] met-enkephalin binding by various compounds was met-enkephalin = d-ala2-mephe4 , met ( 0 ) ol enkephalin ) greater than leu-enkephalin greater than morphine with half-maximal inhibitory constants ( ic50 ) of approx .
C0014298
enkephalin
C0014294
leu-enkephalin