Figure 2.

Concentration-dependent photolabeling of mVDAC1 by KK174 demonstrates saturation and a stoichiometry of one. A, deconvoluted spectra of mVDAC1 photolabeled with KK174 at 0, 10, 30, and 200 μm. The theoretical average masses of unlabeled mVDAC1, singly labeled mVDAC1, and doubly labeled mVDAC1 are 32,154, 32,534, and 32,914 Da, respectively. B, scatter plot of the photolabeling efficiency of mVDAC1 by KK174. Data are fit with a four-parameter logistic equation, which yields an apparent EC₅₀ of 15.3 μm and Hill slope of 1.6.