Mitochondrial outer membrane contains a protein producing nonspecific diffusion channels.

Vesicles permeable to sucrose, but not to high molecular weight dextrans, were produced when fragments of mitochondrial outer membrane obtained from rat liver or mung bean seedlings were fused with liposomes of soybean phospholipids. By using this reconstitution assay, the channel-forming protein in the mung bean mitochondria was identified as protein(s) with an apparent molecular weight of 30,000 through differential detergent extraction and centrifugation in a sucrose density gradient. The channel was nonspecific, and allowed the diffusion of saccharides of up to 2000 to 8000 daltons.