C. The in vitro synthesized [35S]Met-labeled Bax E69C protein with or without the additional mutations (G108E and/or S184V) were activated by the in vitro synthesized [35S]Met-labeled tBid L105C protein and targeted to the Bax-/-/Bak-/- mitochondria that were pretreated with NEM. The resulting mitochondria were isolated and oxidized by CuPhe for 0 or 30 min. The resulting "0 min" samples (1 equivalent each) and "30 min" samples (1 equivalent each) were analyzed by non-reducing SDS-PAGE and phosphor-imaging. The remaining "30 min" samples (4 equivalent each) were immunoprecipitated (IP) by either Bax- or tBid-specific antibody, and then analyzed by non-reducing SDS-PAGE and phosphor-imaging. The identities of the four major products, indicated on the right side of the image, were based on their Mr and recognition by the respective antibody. n = 2. 