. Author manuscript; available in PMC: 2015 Mar 6.

Published in final edited form as: FEBS Lett. 1986 Apr 21;199(2):269–274. doi: 10.1016/0014-5793(86)80493-8

Table 1.

Competition for [³H]XAC binding to human platelet membranes

Compound	K_i (μM)
1,3-Dipropyl-8-(H₂N(CH₂)₂NHCOCH₂-O-phenyl)xanthine (XAC)	0.017
1,3-Diethyl-8-phenylxanthine (DPX)	0.19
5′-N-Ethylcarboxamidoadenosine	0.33
1,3-Dipropyl-8-phenylxanthine	1.0
8-Phenyltheophylline	1.7
1,3-Dipropyl-8-(p-HO₂CCH₂O-phenyl)-xanthine (XCC)	1.8
1,3-Dipropyl-8-(p-sulfophenyl)xanthine	2.4
N⁶-R-Phenylisopropyladenosine (R-PIA)	5.7
8-(p-Sulfophenyl)theophylline	7.2
Theophylline	29
Caffeine	51
ATP	> 100 (25%)
Adenine	> 100 (19%)
Inosine	> 100 (1%)

Binding of 1 nM [³H]XAC was measured for 90 min at 37°C. K_i values are means of 2 experiments done in triplicate. For K_i values above 100 μM, the percentage inhibition of [³H]XAC binding at 100 μM is given in parentheses