Enzymatic polymerization of amphiphilic alkyl tyrosine derivatives from emulsions

Horseradish peroxidase catalyzed polymerizations of amphiphilic derivatives of d- and l-isomers of tyrosine have been carried out in micellar solutions. The rate of polymerization has been found to be maximum at a pH of 6.1–6.2 and showed a second-order dependence on the monomer concentration. This enzyme shows stereospecificity towards the d-isomer compared to the l-isomer, which is consistent with the aqueous reaction with underivatized isomers of tyrosine. The resulting polymers, having a molecular weight of 2700, have been characterized by UV-Vis spectroscopy and 1H NMR. The polymer shows surface activity at the air-water interface unlike the corresponding monomer, which aggregates under identical conditions.