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. Author manuscript; available in PMC: 2014 Jan 17.
Published in final edited form as: J Am Chem Soc. 2013 Jan 31;135(6):2198–2206. doi: 10.1021/ja308493k

Figure 3.

Figure 3

Cyclic voltammograms showing the potential and time dependence of inhibition of CODH ICh by cyanide. Experimental conditions: 25 °C, 0.2 M MES buffer (pH 7.0), scan rate 1 mV/s. (a) After a complete cycle, KCN was injected into the electrochemical cell at −0.74 V to give a final concentration of 1 mM. Subsequent scans reveal the release of CN− as the potential is taken below −0.6 V, and rebinding of CN− on the return oxidative scan. (b) Same as (a) except that CN− is injected (also to a final concentration of 1 mM) at −0.6 V, i.e., near the end of the first cycle while the potential becomes more negative. This experiment clearly shows CN− binding and then dissociating from the enzyme as the potential goes below −0.65 V. (c) Result of fitting the Nernst equation from the red trace of (a): a value of n = 1.3 is obtained.