INTERACTIONS BETWEEN OCTYL-BETA-D-GLUCOSIDE AND ALPHA-AMINO-ACIDS OR SMALL PEPTIDES

The interactions between octyl-~-D-glucoside and glycine in water have been investigated by surface tension, viscosity, and density measurements. The results show that the a-amino acid causes an unexpected lowering of the critical micellar concentration of octyl-t~-D-glucoside. Such a finding has been interpreted in terms of dipole-dipole interactions between the hydrophilic site of the surfactant and the peptidic cosolutes. From three to seven amino acid molecules have been estimated to be coordinated with each glucoside unity in the micellar state. The research has been extended to glycine oligopeptides and L-lysine. The latter compound has effects similar to those observed with glycine whereas diglycine and triglycine show weaker effects on the micellization process.