<title>Fluorescence studies of a labeled model peptide in membrane and micellar media</title>

Abstract

Both micellar and lipid membrane systems have been used as models to provide further information regarding peptide properties in biological systems. Peptides are basic architectural units in nature and the study of their properties in membranes and other non-homogeneous media is of fundamental importance. We present the results for a time-resolved and steady state fluorescence study of two 4-methoxy-naphthalene labelled twelve amino acid residue model peptides that we have synthesised. One peptide, with a N-tert-Butoxycarbonyl (BOC) modified N-terminal, was incorporated into small unilamellar vesicles of L-(alpha) dipalmitoylphosphatidycholine (DPPC) and the other, with a free amino group, into inverse micelles of sodium bis (2-ethylhexyl) sulfosuccinate (AOT) in 2,2,4-trimethylpentane. Steady state fluorescence and time-resolved fluorescence lifetime and anisotropy measurements show the first peptide to be situated in the lipid bilayer. In the inverse micelle system there is evidence for the peptide being situated at the surfactant waterpool interface.