Partial purification of the receptor protein essential for import of pre-ornithine aminotransferase into mitochondria.

The isolated mitochondrial outer membrane fraction strongly inhibits the import of pre-ornithine aminotransferase, but other membranes such as rough microsomes did not. This inhibition seems to be caused by a receptor in the isolated outer membrane which binds competitively pre-ornithine aminotransferase. The mitochondrial outer membrane could be solubilized using detergent. And a receptor for pre-ornithine aminotransferase was partially purified by ammonium sulfate fractionation followed by column chromatography on Sephacryl S-300. Liposomes reconstituted from the partially purified receptor and lecithin could inhibit the import of pre-ornithine aminotransferase into mitochondria and bind the precursor.