Fig. 3. Isolated B50 cell mitochondria contain Bak, but not Bax; inhibition of tBid-induced cytochrome c release by anti-Bak antibodies. (A) Mitochondria and whole B50 cells, each containing 20 µg protein, were analysed in western blots developed with anti-Bak and anti-Bax antibodies. (B) Mitochondria (150 µg protein) were pre-incubated with or without anti-Bak G-23 antibodies (1 µg) for 30 minutes. tBid was added and mitochondrial cytochrome c determined at the times indicated (graph).