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. Author manuscript; available in PMC: 2015 Oct 14.
Published in final edited form as: Int J Biochem Cell Biol. 2010 Mar 17;42(6):1007–1018. doi: 10.1016/j.biocel.2010.03.002

Table 3.

Kinetic and thermodynamic parameters for imipramine binding to hα4β2 AChRs in different conformational states determined by non-linear chromatography studies.

Parameter κ-BTx treated columna Epibatidine treated columnb
koff (s−1) 0.090 ± 0.001 0.076 ± 0.002
kon (s−1 μM−1) 0.229 ± 0.008 0.192 ± 0.003
Ka (μM−1) 2.54 ± 0.07 2.52 ± 0.08
ΔG20 (kJ mol−1) −35.9 ± 0.1 −35.9 ± 0.1

The koff and Ka values were empirically determined by non-linear chromatography using Eqs. (5) and (6), respectively, whereas the kon values were calculated as kon = koff·Ka. ΔG20 values were calculated using Eq. (4).

a

The elution of imipramine from the CMC-hα4β2 AChR column was performed in the presence of κ-BTx (the AChR is mainly in the resting state).

b

The elution of imipramine from the CMC-hα4β2 AChR column was performed in the presence of (±)-epibatidine (the AChR is mainly in the desensitized state).