Polymer synthesis hydrolase-catalyzed

In this section, enzymes in the EC 2.4. class are presented that catalyze valuable and interesting reactions in the field of polymer chemistry. The Enzyme Commission (EC) classification scheme organizes enzymes according to their biochemical function in living systems. Enzymes can, however, also catalyze the reverse reaction, which is very often used in biocatalytic synthesis. Therefore, newer classification systems were developed based on the three-dimensional structure and function of the enzyme, the property of the enzyme, the biotransformation the enzyme catalyzes etc. [88-93]. The Carbohydrate-Active enZYmes Database (CAZy), which is currently the best database/classification system for carbohydrate-active enzymes uses an amino-acid-sequence-based classification and would classify some of the enzymes presented in the following as hydrolases rather than transferases (e.g. branching enzyme, sucrases, and amylomaltase) [91]. Nevertheless, we present these enzymes here because they are transferases according to the EC classification. 

According to the advantages mentioned above, enzyme-catalyzed polymer syntheses are also of increasing interest. Typical examples of enzymatically produced macromolecules are the synthesis of polysaccharides and polyesters using hydrolases, the production of biopolymers like cellulose, xylan, chitin, or hgnin by hydrolases or peroxidases, and the synthesis of polyaromatic... 

Enzymatic polymerization has emerged in the last few decades as a field of considerable interest and commercial promises. It proceeds with high regio-, enantio-, and chemos-electivity under relatively mild conditions. So far, enzymes have been used to synthesize polyesters, polysaccharides, polycarbonates, polyphenols, polyanilines, vinyl polymers, and poly(amino acid)s. Namely, the lipase B of Candida antarctica (Cal-B, a serine hydrolase) immobilized on polyacrylic resin (Novozyme 435) has proven to be a very versatile catalyst in terms of reaction conditions and acceptance of various substrates. For example, this enzyme has been successfully used to synthesize polyesters. ° However, little has been reported so far on the synthesis of polyamides catalyzed by enzymes. " ... 

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