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Table 3 Ki values for Inhibition of [3 H]granisetron binding to wildtype and mutant 5-HT3ASRs.

From: Identification of critical residues in loop E in the 5-HT3ASR binding site

 

Ki (Inhibition of [3H]granisetron binding) nM

Receptor

5-HT (nM)

MCPBG (nM)

d -tc (nM)

Lerisetron

Wildtype

74 ± 17

3.0 ± 0.55

6 ± 2.1

0.8 ± 0.19

Y140A

97 ± 20

22 ± 6.1

300 ± 120

2.1 ± 0.33

V141A

82 ± 9.2

4.1 ± 0.50

4.7 ± 0.87

0.20 ± 0.02

Y142A

(8 ± 2.0) × 10 3

470 ± 90

39 ± 19

130 ± 28

V143A

22 ± 2.2

2.0 ± 0.44

22 ± 2.6

1.5 ± 0.41

H145A

29 ± 6.5

0.60 ± 0.10

19 ± 2.6

0.42 ± 0.04

R146A

61 ± 14

15 ± 4.9

29 ± 4.9

2.3 ± 0.31

E148A

73 ± 11

8.2 ± 1.5

14 ± 1.7

2.8 ± 0.53

Q150A

170 ± 29

27 ± 3.9

9.3 ± 1.3

1.1 ± 0.21

N151A

140 ± 20

1.8 ± 0.18

9.3 ± 1.4

3.7 ± 0.62

Y152A

(1.8 ± 0.4) × 10 3

73 ± 26

60 ± 19

150 ± 36

K153A

270 ± 34

7.7 ± 2.0

17 ± 3.0

3.0 ± 0.66

  1. IC50 values were determined from competition binding data using [3H]granisetron as described in the methods section. Ki values were calculated from the IC50 using the Cheng-Prusoff equation, the Kd value, and the concentration of [3H]granisetron (typically equal to the Kd). Each value represents the combined data from at least four experiments and is represented as Ki ± SE. Values in bold type indicate changes in Ki greater than or equal to 10 fold on mutant vs. wt receptors.