Table 3. Functional properties of cysteine mutant receptors.

Mutants	EC50 (μM)	n H	Imax (pA/picofarad)	n	ΔΔG (Kcal.mol-1)	ΔΔGINT (Kcal.mol-1)
rP2X2R-WT	4.1 ± 0.9	0.7 ± 0.1	49.1 ± 10.6	20	0
rP2X2R-T	3.7 ± 0.6	1.3 ± 0.3	51.7 ± 9.3	30	0
V48C	5.8 ± 0.5	1.3 ± 0.1	66.8 ± 9.1	5	0.24 ± 0.03
I328C	3.9 ± 0.6	1.5 ± 0.3	73.1 ± 11.4	5	0.09 ± 0.02
H33C	2.3 ± 0.5	1.3 ± 0.3	35.8 ± 8.3	5	-0.29 ± 0.13
S345C	6.3 ± 0.9	1.2 ± 0.1	40.5 ± 7.6	5	0.30 ± 0.08
V48A	3.2 ± 0.6	1.6 ± 0.1	25.4 ± 2.1	7	-0.1 ± 0.11
I328A	0.4 ± 0.1	1.7 ± 0.2	31.7 ± 6.1	6	-1.31 ± 0.15
H33A	4.2 ± 0.6	1.6 ± 0.3	41.7 ± 8.3	6	0.08 ± 0.07
S345A	12.1 ± 0.7	1.3 ± 0.2	27.5 ± 5.8	7	0.69 ± 0.03
F44C	0.81 ± 0.1	0.9 ± 0.3	39.2 ± 2.1	4	-0.89 ± 0.07
A337C	6.2 ± 0.5	1.2 ± 0.4	30.1 ± 4.1	4	0.30 ± 0.05
V48C/I328C	17.8 ± 2.0	0.9 ± 0.2	12.8 ± 1.8	28	0.91 ± 0.07	0.59 ± 0.03
H33C/S345C	7.3 ± 1.1	1.3 ± 0.2	95.9 ± 12.3	10	0.36 ± 0.10	0.33 ± 0.10
V48A/I328A	5.4 ± 0.4	1.3 ± 0.3	42.0 ± 6.5	5	0.22 ± 0.04	1.60 ± 0.04
H33A/S345A	35.7 ± 0.5	1.4 ± 0.1	33.1 ± 4.1	7	1.32 ± 0.01	0.66 ± 0.01
F44C/A337C	1.5 ± 0.5	1.5 ± 0.2	41.4 ± 1.5	4	-0.52 ± 0.19	0.10 ± 0.18
rP2X2R-T after DTT	3.9 ± 0.5	0.7 ± 0.2	67.3 ± 11.2	10	0
V48C after DTT	5.5 ± 0.5	1.3 ± 0.1	67.1 ± 8.7	5	0.23 ± 0.05
I328C after DTT	4.0 ± 0.6	1.6 ± 0.3	70.2 ± 14.3	5	0.1 ± 0.03
H33C after DTT	3.1 ± 0.3	1.3 ± 0.3	35.8 ± 8.3	5	-0.11 ± 0.06
S345C after DTT	6.5 ± 0.7	1.2 ± 0.1	40.5 ± 7.6	5	0.32 ± 0.13
V48C/I328C after DTT	3.6 ± 0.4	1.1 ± 0.2	21.1 ± 4.6	15	0.27 ± 0.19	-0.31 ± 0.07
V48C/I328C after H2O2	17.9 ± 1.9	0.7 ± 0.1	11.9 ± 1.7	6	0.92 ± 0.06	0.59 ± 0.03
H33C/S345C after DTT	3.19 ± 0.3	1.4 ± 0.2	97.2 ± 11.9	10	-0.09 ± 0.05	-0.12 ± 0.05
H33C/S345Cafter H2O2	6.4 ± 0.5	1.4 ± 0.3	63.8 ± 7.8	5	0.32 ± 0.05	0.28 ± 0.05

The data represent the mean ± S.E.M. of the numbers of cells studied (n).