the density of alpha-lt receptors [ which are probably composed of , or include , membrane protein ( s ) ] varies between 0.6 and 0.88 pmol/mg of synaptosome protein , their affinity is very high ( ka of the order of 10 ( 10 ) m-1 ) , their association rate is fast , and their dissociation rate slow .
C0025252
membrane protein
C0033684
protein