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. Author manuscript; available in PMC: 2008 Aug 21.
Published in final edited form as: J Am Chem Soc. 2006 May 3;128(17):5802–5812. doi: 10.1021/ja060070r

Figure 4.

Figure 4

A representative ITC experiment showing the titration of arylsulfonamide ligand into a solution of bovine carbonic anhydrase II (BCA). The sample cell contained 10.0 μM BCA in 20 mM sodium phosphate buffer pH 7.5 and 0.6% DMSO-d6 (v/v) (to solubilize the arylsulfonamide and to allow for NMR quantitation, see Experimental Section). The injection syringe contained 103 μM ArGly2O- (1) in the same buffer. One injection of 2.0 μL preceded 24 injections of 12.0 μL. The interval between injections was 4 min. (A) Data after baseline correction. (B) Data after peak integration, blank subtraction, and normalization to moles of injectant. The solid line shows a sigmoid fit to a single-site binding model (with the first datum omitted). The dissociation constant (Kd = 0.20 μM), enthalpy of binding (ΔH° = -12.6 kcal mol-1), and stoichiometry of binding (N = 1.02) were the fitting parameters in the analysis. See Experimental Section for details.