Kinetics of spontaneous and plasma-stimulated sphingomyelin transfer.
The mechanism of transfer of a pyrene-labeled sphingomyelin (PySM) between different lipid compartments was studied by a fluorescence technique. The first-order kinetics are independent of donor and acceptor concentration and the identity of the acceptor; the rates are accelerated by 'structure-breaking' solutes and inhibited by 'structure-making' solutes. These observations are consistent with the transfer of PySM occurring via the aqueous phase that separates the donor and acceptor compartments. We have partially purified a plasma factor that stimulates the transfer rate. Our in vitro results suggest that both spontaneous and stimulated transfer might contribute to the redistribution of sphingomyelin in vivo,
D016633:Apolipoprotein A-II; D001053:Apolipoproteins / Q000378:metabolism; D006801:Humans; D007700:Kinetics; D011721:Pyrenes; D013050:Spectrometry, Fluorescence; D013109:Sphingomyelins / Q000097:blood / Q000378:metabolism*; D013329:Structure-Activity Relationship
D016633:Apolipoprotein A-II; D001053:Apolipoproteins; D011721:Pyrenes; D013109:Sphingomyelins