Reconstitution of cytochrome b5 into lipid vesicles in a form which is nonsusceptible to attack by carboxypeptidase Y.

Pig liver cytochrome b5 is reconstituted into lipid vesicles by a method whereby cytochrome b5-lysophospholipid micelles are fused with liposomes. The reconstitution method inserts cytochrome b5 into the lipid bilayer in a mode which renders the C-terminal part of cytochrome b5 nonsusceptible to attack by carboxypeptidase Y. The effect of the lipid composition of the vesicles on the mode of insertion has been examined, when cytochrome b5 is reconstituted using the presently described method and methods previously used to reconstitute this protein, namely the direct incorporation method and the cholate dialysis method.