|
Compounds
|
Affinity (nM)
|
Selectivity
|
|---|
|
α-1
|
α-2
|
α-3
|
α-1 / α-2
|
α-1 / α-3
|
|---|
|
Cardenolides
|
|
Ouabain
|
50 ± 10
|
70 ± 12
|
50 ± 7
|
0.7
|
1.0
|
|
Digoxin
|
104 ± 11
|
25 ± 4
|
27 ± 2
|
4.2
|
3.9
|
|
Uzarigenin-rhamnoside
|
90 ± 20
|
96 ± 7
|
122 ± 9
|
0.9
|
0.7
|
|
Uzarigenin
|
1,100 ± 120
|
883 ± 56
|
1,278 ± 142
|
1.3
|
0.9
|
|
Gitoxin
|
123 ± 8
|
85 ± 3
|
108 ± 17
|
1.5
|
1.1
|
|
Gitoxigenin
|
500 ± 90
|
1,180 ± 190
|
1,050 ± 100
|
0.4
|
0.5
|
|
Bufadienolides
|
|
Gamabufotalin-rhamnoside
|
30 ± 7
|
36 ± 10
|
17 ± 2
|
0.8
|
1.8
|
|
Gamabufotalin
|
243 ± 48
|
247 ± 30
|
236 ± 14
|
1.0
|
1.0
|
|
Hellebrin
|
86 ± 18
|
218 ± 52
|
175 ± 20
|
0.4
|
0.5
|
|
Hellebrigenin
|
103 ± 19
|
198 ± 51
|
191 ± 23
|
0.5
|
0.5
|
- *The data were obtained from three independent experiments.
- *The data for uzarigenin, uzarigenin-rhamnoside, gitoxigenin and gitoxin are from Katz et al. [5] and are included here.
- *Ouabain binding affinities for the three isoforms appear lower than analyzed previously [5]. The lower values in [5] are the result of full Scatchard analysis for ouabain which excludes all non-specific binding. The selectivity is the same even though the absolute values of KD are higher. All the experiments were done in the same way, e.g. we have left all the values obtained in the displacement experiments.
