Table 4.

The binding kinetics of unlabeled CCPA in the absence or presence of 10 μM PD81,723 or 1 mM GTP

Compound	kon (M−1·min−1)a	koff (min−1)a	KD (nM)b
CCPAc	1.1 ± 0.2 × 107	1.2 ± 0.3	109 ± 12
CCPA (184 nM)d	8.2 ± 2.0 × 106e	0.85 ± 0.23e	104 ± 22e
CCPA (552 nM)d	9.0 ± 2.5 × 106e	1.1 ± 0.3e	122 ± 27e
CCPA (1840 nM)d	6.7 ± 2.7 × 106e	0.91 ± 0.40e	136 ± 47e
CCPA + 1 mM GTPc	1.3 ± 0.4 × 107f	2.2 ± 0.6f	169 ± 40f
CCPA + 10 μM PD81,723c	1.1 ± 0.1 × 107	0.31 ± 0.04	28 ± 3
CCPA (43 nM) + 10 μM PD81,723d	1.4 ± 0.2 × 107g	0.34 ± 0.06g	24 ± 3g
CCPA (128 nM) + 10 μM PD81,723d	1.0 ± 0.1 × 107g	0.32 ± 0.03g	32 ± 3g
CCPA (427 nM) + 10 μM PD81,723d	0.7 ± 0.1 × 107g	0.24 ± 0.03g	34 ± 4g

Values are means ± SEM of three separate experiments each performed in duplicate.

^ak_on (k₃) and k_off (k₄) of unlabelled CCPA in the absence or presence of 10 μM PD81,723 or 1 mM GTP were determined in [³H]-DPCPX (2.6 nM) competition association assays.

^bKinetic K_D = k_off/k_on; k_on (k₃) and k_off (k₄) values of unlabelled CCPA were generated from [³H]-DPCPX (2.6 nM) competition association assay at 25°C.

^cData obtained by globally analysing three concentrations of unlabelled CCPA.

^dData obtained by analysing a single concentration of unlabelled CCPA.

^eNot significantly different from its respective values obtained by globally analysing three concentrations of unlabelled CCPA; P > 0.05; Student's t-test.

^fNot significantly different from its respective values in the absence of 1 mM GTP; P > 0.05; Student's t-test.

^gNot significantly different from data obtained by globally analysing three concentrations of unlabelled CCPA in the presence of 10 μM PD81,723; P > 0.05; Student's t-test.