THE EFFECT OF REACTION CONDITIONS ON MONTMORILLONITE-CATALYZED PEPTIDE FORMATION

Oligomerization of glycine (gly) and diglycine (gly(2)) on montmorillo nite was performed as cyclic, drying-wetting process at temperatures b elow 100 degrees C, under varying reaction conditions. The influence o f substrate/clay ratio, temperature and pH was found to be different f or amino acid (AA) dimerization, cyclic anhydride (CA) formation and p eptide chain elongation. High temperatures and neutral pH favour CA fo rmation over diglycine production. An AA/catalyst ratio of 0.2 mmol/g leads to optimal yields. This supports the assumption that amino acid dimerization and CA formation take place at the edges of clay particle s. Peptide chain elongation, starting from gly(2), produces higher yie lds at higher temperatures and neutral pH.