[Variation of cell membrane lipid composition by means of lipid transfer proteins. Properties of the protoplast membrane of Micrococcus lysodeikticus after incorporation of phosphatidylcholine].

After incorporation of phosphatidylcholine (PC) into the protoplast membrane of M. lysodeikticus by protein mediated transfer from PC liposomes, the activity of some membrane bound respiratory chain enzymes was studied. It was found that incorporation of PC decreases the rates of oxidation of exogenous substrates (NADH, malate) but the level of endogenous respiration was not changed. Ferricyanidreductase activity of ghosts of M. lysodeikticus was not dependent upon the PC content of protoplasts. PC containing protoplasts showed a higher osmotic stability than unmodified protoplasts. It is concluded that the incorporation of PC into the protoplasts results in resealing, i. e. in the repair of local defects in the protoplast membrane.