. Author manuscript; available in PMC: 2010 Mar 31.

Published in final edited form as: Biochemistry. 2009 Mar 31;48(12):2630–2642. doi: 10.1021/bi801853a

TABLE 4.

Comparison of k_on, k_off, and K_d values for wild-type, I56C/Q333C and D328R Gα_i1. Values are from an average of 4 trials (wild type) or 2 trials (I56C/Q333C and D328R).

KB-752 (selective for Gα_i-GDP)	k_on (1/M • s)	k_off (s⁻¹)	K_d (μM)
WT Gα_i GDP	21,100 ± 5,800	0.06 ± 0.01	2.84 ± 0.81
I56C/Q333C Gα_i GDP	7,750 ± 250	0.22 ± 0.03	28.2 ± 2.9
D328R Gα_i GDP	8,560 ± 650	0.01 ± 0.001	1.28 ± 0.02
KB-1753 (selective for Gα_i-GDP•AlF₄)
WT Gα_i GDP •AlF₄⁻	22,900 ± 2,300	0.025 ± 0.001	1.1 ± 0.1
I56C/Q333C Gα_i GDP•AlF₄⁻	16,800 ± 1,700	0.006 ± 0.0008	0.36 ± 0.01
D328R Gα_i GDP•AlF₄⁻	8,810 ± 1,390	0.003 ± 0.0004	0.26 ± 0.04