FLUORESCENCE QUENCHING IN MEMBRANE PHASE

Membrane-related events can be investigated when the fluorescence of a n intramembrane fluorophore is quenched by molecules that are dissolve d in lipid phase. In this case the bimolecular quenching constant char acterises the relative transport rate of the fluorophore and quencher molecules in the membrane interior and thereby it is related to the dy namics or structure of the membrane. Unlike classic quenching experime nts, the crucial point in such studies is that the concentration of th e quencher in the lipid phase differs from that in the bulk. As a cons equence, it is usually described by different models, or regarded as t he total concentration added. Here a simple fluorometric study is pres ented for distinguishing between the solvation mechanisms (partition o r binding) of quencher molecules in membrane phase. (C) 1995 Academic Press, Inc.