Open AccessThe components of merocyanine‐540 absorption spectra in aqueous, micellar and bilayer environments
Author(s) -
KASCHNY Peter,
GOÑI Félix M.
Publication year - 1992
Publication title -
european journal of biochemistry
Language(s) - English
Resource type - Journals
eISSN - 1432-1033
pISSN - 0014-2956
DOI - 10.1111/j.1432-1033.1992.tb17145.x
Subject(s) - merocyanine , bilayer , chemistry , monomer , dimer , absorption spectroscopy , absorption (acoustics) , aqueous solution , analytical chemistry (journal) , photochemistry , micelle , spectroscopy , chemical physics , materials science , membrane , organic chemistry , polymer , optics , physics , photochromism , biochemistry , quantum mechanics , composite material
Spectral‐data‐processing and curve‐fitting techniques have been applied to the decomposition of merocyanine‐540 absorption spectra in aqueous, micellar and bilayer environments. The various resolved component bands have been assigned to dye monomers, dimers, or larger aggregates, either in polar or non‐polar environments. The analysis of spectral parameters (λ max and integrated intensity) of the overall spectra and of each component has revealed that merocyanine 540 is a useful probe in studies of membrane structure and dynamics using visible‐absorption spectroscopy. In particular, the monomer λ max and the integrated intensity, i.e. area, of the dimer population are very useful in this respect. The monomer λ max is especially sensitive to polarity changes and is thus useful, e.g. in the precise determination of critical micellar concentrations. The fractional area of the dimer increases with the packing density of the phospholipid‐hydrocarbon region near the interface and is thus very sensitive to changes in vesicle curvature and to the presence of sterols or intrinsic polypeptides in the bilayer.