CONICET | Buscador de Institutos y Recursos Humanos

The thiol group of cysteine takes part in a variety of biochemical reactions. The possible formation of weak hydrogen bonds at receptor sites is of considerable interest, as it might contribute to the biological response. The lipid molecules are essential constituents of biomembranes. Since lipids are highly solvated by water molecules at their polar heads; the water structure on the surface of lipid membranes has a crucial role in biologically important phenomena such as a specific recognition of membrane-bound receptors and trans-membrane transportation of substances. In this work, the interaction of L-cysteine ethyl ester. HCl with lyophilized dipalmitoylphosphatidylcholine (DPPC) liposomes (complex), was studied by infrared (FTIR) and Raman spectroscopies. The results of the FTIR spectroscopy show that the effects of L-cysteine ethyl ester. HCl with the phosphate and carbonyl groups of membranes are qualitatively different. The PO2− antisymmetric stretching band is displaced to lower values wich indicate that L-cysteine ethyl ester. HCl would be able to bond with the phosphate group when the liposomes are dehydrated. It is interesting to note that the C=O vibrational modes of the H-bonded (bond) and nonbonded (free) conformers of the C=O group in lipids in the anhydrous state shows an upward shift in frequency of both population, this would suggests a displacement of water molecules. Raman measurements show displacements in the CH3 symmetric and antisymmetric vibration stretchings and CH2 deformation bands to higher frequencies, would indicate an increase in the packing of the lipids in the dry state induced by L-cysteine ethyl ester. HCl. The S-H mode show a displacement towards higher frequencies in the solid state complex of the Raman spectrum, as compared to the Raman spectrum of the L-cysteine ethyl ester. HCl pure.