Kinetics of Ligand-binding and Oxidation-Reduction Reactions of Cytochrome c from Horse Heart and Candida krusei

Reactions of cytochromes c from horse heart and Candida krusei (a yeast) were studied at 25" under pseudo-first order conditions by a flow technique.The rate law for the reduction of C. krusei by Cr(I1) (pH 6.0, p = 1.0 M) in chloride is kobs = a[Cr(II)]/(l + b[Cr(II)]), where a and b are 1.0 x 10' M-' s-l and 167 f 38 ~-l, respectively.The binding of imidazole (Im) to C. krusei conforms to the rate law k&s = k, + R,[Im] (k, = 1.65 f 0.15 s-l, 4, = 16.4 f 0.3 I@ s-l at 695 nm, pH 7.1, p = 1.00 M) which is consistent with the kf reaction C. krusei + Im ,c C. krusei-Im.* This research was performed