METHODS FOR MAKING PECTIN-BASED MIXED POLYMERS

摘要

This application discloses that two enzymes formerly known in the art as pectin methylesterase (PME) and endopolygalacturonidase (EPG) possess additional catalytic activities as pectin transester synthase (PTES) and pectin transesterase (PTE), respectively. The PTES catalizes the synthetic reaction that covalently cross-links homogalacturonan chains in the primary cell wall via ester bonds. Thus PTES can be employed to form at least one ester bond between two chemical entities, one carrying at least one acid, salt of an acid, or ester group, and one carrying at least one hydroxyl group, e.g., between two polymers, a polymer and a monomeric compound or two monomeric compounds. Further PTES can be employed to form at least one amide bond between two chemical entities, one carrying at least one acid, or ester group, and one carrying at least one amine group, preferably an unsubstituted amine group (-NH2). The pectin transesterase (PTE) disclosed herein catalyzes the hydrolysis of ester bonds between the carboxyl group(s) of galactosyluronic acid residues of one homogalacturonan chain and the O-2 and/or O-3 hydroxyl group(s) of galacturonic acid residues of another homogalacturonan. PTE activity is shown to reduce the viscosity of pectin solutions in vitro. Thus, the PTE enzyme can be used as an additive to modify the fluidity of a variety of food and pharmaceutical preparations containing pectin, in particular, juice, pastes, jellies, and jams.