[Use of protein-mediated lipid exchange for studies of membrane-bound enzymes. Properties of monoamine oxidase activated by phosphatidylcholine].

Protein-mediated lipid exchange between phosphatidylcholine liposomes and hepatoma mitochondria was used to alter the lipid composition of the mitochondria and the resulting changes in the activity of monoamine oxidase were studied. Introduction of additional amounts of phosphatidylcholine substantially increased the activity of the enzyme, but did not affect its substrate specificity and the enzyme sensitivity to inhibitors (chlorgyline and deprenyl). The thermal stability of the enzyme was not increased under supplementation of the hepatoma mitochondria with phosphatidylcholine.