Peptide synthesis Catalyzed by Micellur Models of Metalloenzymes

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The purpose of this project was to develope an efficient method for the synthesis of peptides by the use of some micellar systems containing lipophilic ligandmetal ion complexes as the catalysts. Various lipophilic ligands were newly synthesized; they contain imidazole group(s) for the chelation with metal ions and nucleophilic hydroxyl group(s) attack ester substrates. These ligands were allowed to form complexes with metal ions, Zn^<2+> and Cu^<2+>, in aqueous micelles of cationic, anionic, or non-ionic surfactants, as well as in reverse micelles of AOT surfactant inhexane. Some of these co-micellar systems exhibited remarkable catalytic activities in the hydrolysis of active esters, such as p-nitrophenyl picolinate. They were also active in the acyl transfer reactions between alcohols in AOT reverse micelles when DMF was used as the core solvent.Unfortunately, however, the above systems did show enough activity for the condensation of amino acid esters to form peptides with reasonable yields. Further works are required to design more powerful catalysts. With regard to this, we were able to prepare a novel surfactant ligand and found it to be a remarkably active catalyst when complexed with Cu^<2+> ion, although the applicability to peptide synthehas not yet been examined.