TABLE I.

Biotinyl Conjugates of Adenosine Receptor Ligands^a

graphic file with name nihms-401325-t0001.jpg

Biotinyl (B) derivative	K_i (no avidin)	K_i (+ avidin)
(1) B–ADAC	11.4	36
(2) B–NH(CH₂)₅CO-ADAC	18	35
(3) B–NH(CH₂)₄CHNH₂CO–ADAC (d-configuration)	8.9	n.d.^b
(4) B–XAC	54	>500
(5) B–NH(CH₂)₅CO–XAV	50	>500
(6) B–NH(CH₂)₅CO-Gly₃–XAC	50	260

K_i values (nanomolar) are for inhibition of the binding of N⁶-[³H]phenylisoproplyl-adenosine or N⁶-[³H]cyclohexyladenosine to rat brain membrane A₁-adenosine receptors in the presence or absence of precomplexed avidin (1 μM). Data from Refs. 4 and 5.

n.d., not determined.