The voltage-dependent anion channel (VDAC) is located in the:
Exchange of metabolites between cytosol and mitochondria requires regulated permeability across the outer membrane, which unlike inner membrane does not maintain large electrochemical gradient. Voltage-dependent anion channel, VDAC, also called mitochondrial porin, forms the major outer membrane channel present in thousands of copies. Mammalian cells express three isoforms VDAC1, VDAC2 and VDAC3 that assemble as 19-stranded beta-barrel pores with N-terminal helix gating, permitting diffusion of ions, ATP, ADP, succinate, citrate, malate, NADH and other molecules up to about 5 kDa with cut-off
Ref: Alberts et al., Molecular Biology of the Cell, 7th ed., Chapter 14: VDAC and Mitochondrial Metabolite Transport.
