Micellar aggregates of the nonionic peptide derivative Boc-Leu-Asn-OCH
2CH3 (1) have been observed in aqueous solution, Evidence for micelle
formation of the above peptide was obtained by conductometric and fluo
rescence spectroscopic techniques. Keto-enol tautomeric ratio of benzo
ylacetone was taken for the determination of critical micelle concentr
ation (cmc). From the values of critical micelle concentration of the
above peptide Delta G(m)(0), Delta H-m(0), Delta S-m(0) and Delta C-p(
0) have been estimated, and it was found that there are two processes
with regard to these parameters. In both the processes, the prime caus
e for aggregation seems to be the stability of the micelle due to the
enthalpic contribution. The spherical micellar model was used to expla
in the aggregation number and the thermodynamic parameters.