Protease-catalysed peptide synthesis in aqueous-organic two-phase systems: reactant precipitation and interfacial...

Peptides can be efficiently synthesized by the proteases thermolysin and pepsin acting in aqueous-organic two-phase systems similar to those reported previously. However, a number of problems can prevent successful reactions in these systems, with these and other proteases: (1) Complexes between amino acid reactants that are sparingly soluble in both phases may be precipitated, though their solubility behavior is complex; (2) the enzyme may be subject to rapid inactivation by contact with the phase interface, and the rate of this is unusually dependent on the nature of the solvent; and (3) the reaction rate is usually slow.