INFLUENCE OF FREEZE-CONCENTRATION EFFECT ON PROTEINASE-CATALYZED PEPTIDE-SYNTHESIS IN FROZEN AQUEOUS SYSTEMS

Freezing of the reaction mixture is a powerful tool in proteinase-cata lysed peptide synthesis. In this study, the considerable yield-increas ing effect of freezing has been analysed by physical and analytical me thods. H-1-NMR relaxation time measurements have been used to determin e the amount of unfrozen water in partially frozen systems thus quanti fying the extent of the 'freeze concentration effect' for the first ti me. Comparative studies in ice and at room temperature verify the impo rtance of freeze-concentration which, however, is not sufficient for a complete understanding of the observed effects. Furthermore, the phas e behaviour of frozen systems is discussed. (C) 1997 Elsevier Science B.V.