Oxidoreductases polymer modifications

In living cells, various oxidoreductases play an important role in maintaining the metabolism of living systems. So far, peroxidase containing Fe-active site, laccase containing Cu-active site, tyrosinase (polyphenol oxidase, Cu-active site), bilirubin oxidase (Cu-active site), etc, have been reported to act as catalyst for oxidative polymerization of phenol and aniline derivatives and for polymer modification via oxidative coupling. 

Polymer Modification by Oxidoreductases. Tyrosinase (polyphenol oxidase, a copper-containing monooxygenation enzyme) was used as catalyst for modification of chitosan. The enzymatic treatment of chitosan film in the presence of tyrosinase and phenol derivatives produced a new material of chitosan derivative (309). During the reaction, imstable o-quinones were formed, followed by the reaction with chitosan to give the modified chitosan. In the enzymatic treatment of p-cresol with a low concentration of chitosan (<1%), the reaction solution was converted into a gel (310). 

This overview briefly surveys the use of enzymatic and wholecell approaches in polymers. Three types of reactions are covered polymer syntheses, polymer modifications, and polymer hydrolyses. Thus far, most of the enz3une-related R D activities involve hydrolases, oxidoreductases, and transferases, with occasional use of lyases and isomerases. Whole-cell methods continue to be valuable in both academic and industrial labs. All these research areas display continued vitality and creativity, as evidenced by the large number of publications. Advances in biotechnology have provided new and improved enzymes and additional tools. Also included in diis overview is the related topic of biomaterials. 

Enzymes are conunonly classified, via a system of Enzyme Commission (EC) numbers, into six divisions oxidoreductases, transferases, hydrolases, lyases, isomerases, and ligases (34). In this work, we are concerned with three types of polymer reactions polymer syntheses, polymer modifications, and polymer degradation and hydrolyses. For these reactions, only hydrolases, oxidoreductases, and transferases are being used extensively in polymers and biomaterials. A summary is given in Table 1. 

Oxidoreductases comprise a large class of enzymes that catalyze biological oxidation/reduction reactions. Because so many chemical transformation processes involve oxidation/reduction processes, the idea of developing practical applications of oxidoreductase enzymes has been a very attractive, but quite elusive, goal for many years [83], Applications have been sought for the production of pharmaceuticals, synthesis and modification of polymers, and the development of biosensors for a variety of clinical and analytical applications [83], In recent years, the use of oxido-reductive enzymes to catalyze the removal of aromatic compounds from... 

Increasing applications of oxidoreductases for modifying surface properties of synthetic polymers have been reported. A good example is surface modification... 

Peroxidases belong to the class of oxidoreductases containing iron (111) and protoporphyrin IX as the prosthetic groups. Peroxidases catalyze the reduction of peroxides and the oxidation of many organic and inorganic compounds. These enzymes are widely used for the removal of phenolic compounds, decolorization of synthetic dyes, deodorization of swine manure, in enzyme immunoassays, for biofuel production and organic and polymer synthesis (Hamid and Rehman, 2009). Peroxidases have also been used for the surface modification of poly-p-phenylene-2,6-benzo-bisthiazole (PBO), polyethylene, and grafting of acrylamide onto kevlar fibers. 

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