Growth of epithelial cells on films of enzymatically synthesized poly(gallic acid) crosslinked to carboxymethylcellulose

Enzyme-mediated poly(gallic acid) crosslinked to carboxymethylcellulose toward a novel material for skin tissue engineering.

Enzymes as Green Catalysts for Precision Macromolecular Synthesis

The present article comprehensively reviews the macromolecular synthesis using enzymes as catalysts. Among the six main classes of enzymes, the three classes, oxidoreductases, transferases, and hydrolases, have been employed as catalysts for the in vitro macromolecular synthesis and modification reactions. Appropriate design of reaction including monomer and enzyme catalyst produces macromolecules with precisely controlled structure, similarly as in vivo enzymatic reactions. The reaction controls the product structure with respect to substrate selectivity, chemo-selectivity, regio-selectivity, stereoselectivity, and choro-selectivity. Oxidoreductases catalyze various oxidation polymerizations of aromatic compounds as well as vinyl polymerizations. Transferases are effective catalysts for producing polysaccharide having a variety of structure and polyesters. Hydrolases catalyzing the bond-cleaving of macromolecules in vivo, catalyze the reverse reaction for bond forming in vitro to give various polysaccharides and functionalized polyesters. The enzymatic polymerizations allowed the first in vitro synthesis of natural polysaccharides having complicated structures like cellulose, amylose, xylan, chitin, hyaluronan, and chondroitin. These polymerizations are "green" with several respects; nontoxicity of enzyme, high catalyst efficiency, selective reactions under mild conditions using green solvents and renewable starting materials, and producing minimal byproducts. Thus, the enzymatic polymerization is desirable for the environment and contributes to "green polymer chemistry" for maintaining sustainable society.

Powering tyrosol antioxidant capacity and osteogenic activity by biocatalytic polymerization

Oxidative polymerization of tyrosol afforded a mixture of oligomers (OligoTyr) which proved to be more active than tyrosol as antioxidant and as stimulator of alkaline phosphatase (ALP) activity when loaded into polylactic acid (PLA) scaffolds.

Horseradish peroxidase (HRP) as a tool in green chemistry

The horseradish peroxidase (HRP) potential in organic synthesis.

Biocatalysis for biobased chemicals

The design and development of greener processes that are safe and friendly is an irreversible trend that is driven by sustainable and economic issues. The use of Biocatalysis as part of a manufacturing process fits well in this trend as enzymes are themselves biodegradable, require mild conditions to work and are highly specific and well suited to carry out complex reactions in a simple way. The growth of computational capabilities in the last decades has allowed Biocatalysis to develop sophisticated tools to understand better enzymatic phenomena and to have the power to control not only process conditions but also the enzyme's own nature. Nowadays, Biocatalysis is behind some important products in the pharmaceutical, cosmetic, food and bulk chemicals industry. In this review we want to present some of the most representative examples of industrial chemicals produced in vitro through enzymatic catalysis.

Automated analysis of synthesized oligorutin and oligoesculin by laccase

The polymerization of phenolic species is an interesting way to generate derivatives with new or improved properties. The structural analysis of these compounds is complex and requires specific analytical techniques. The size exclusion chromatography coupled with an UV detector (SEC-UV) and matrix-assisted laser desorption ionization coupled with a time-of-flight detector (MALDI-TOF) analyses are two methods used to investigate the masses of biopolymers. To analyse the oligomers of rutin and esculin synthesized by the laccase from Trametes versicolor , these two techniques were used and coupled with an automated platform. The conditions of detection by MALDI-TOF were optimized. The parallel synthesis, the preparation of sample, the SEC analysis, and the MALDI spotting were realized automatically on a Chemspeed platform. The MALDI-TOF technique enables the detection of oligomers up to pentamer and nonamer, whereas the SEC-UV permits the detection of about 17-mer for rutin and esculin. The molecular mass distribution is underestimated by MALDI-TOF analysis compared with SEC-UV, but comes to the determination of absolute masses. So these two techniques would be combined to explore the masses and the oligomer distributions.

Structural Diversity of Peroxidase-Catalyzed Oxidation Products ofo-Methoxyphenols

[reaction: see text] The biocatalytic oxidation of o-methoxyphenolic compounds led to a variety of oligophenols (dimers to pentamers) and some of their oxidation products. The reaction was carried out in an aqueous medium at room temperature with hydrogen peroxide as the terminal oxidant in a facile and green route to potentially bioactive compounds. Detailed structural information on the products of peroxidase-catalyzed oxidation of o-methoxyphenols is presented for the first time.

Enzymatic polymerization of tyrosine derivatives. Peroxidase- and protease-catalyzed synthesis of poly(tyrosine)s with different structures

Polymerization of tyrosine derivatives has been carried out by using two enzymes, peroxidase and protease, as catalyst to give poly(tyrosine)s with different structures. Tyrosine ester hydrochlorides were oxidatively polymerized by a peroxidase in a buffer. Using a high buffer concentration produced the polymer in good yields. The resulting polymer was soluble in N,N-dimethylformamide, dimethyl sulfoxide, and methanol but was insoluble in acetone, tetrahydrofuran, and water. The ester moiety of the polymer was subjected to the alkaline hydrolysis, yielding a water-soluble polymer having the amino acid group in the side chain. The peroxidase also catalyzed the oxidative polymerization of N-acetyltyrosine to give the polymer soluble in water. The polymerization of tyrosine ester hydrochlorides proceeded in the presence of papain catalyst to give a polymer of alpha-peptide structure. The polymerization in the buffer of high phosphate concentration efficiently produced the polymer. On the other hand, the polymer formation was not observed in the low buffer concentration. The molecular weight was several thousands and almost constant during the reaction. The morphology of the precipitated polymer was examined. The product of the initial reaction stage was amorphous. After 24 h, the precipitates exhibiting clear birefringence were formed. Scanning electron microscopy observation of the polymer after 72 h showed the formation of a globular crystal in a diameter larger than 50 microm, which was not found by recrystallization of poly(tyrosine).

Peroxidase-catalyzed oxidative polymerization of bisphenols

Oxidative polymerization of bisphenolic monomers has been performed using peroxidase as catalyst in an aqueous organic solvent. Peroxidase induced the polymerization of an industrial product, bisphenol F, consisting of 2,2'-, 2,4'-, and 4,4'-dihydroxydiphenylmethanes. Under the selected conditions, the quantitative formation of the polymer was observed. Among the isomers, 2,4'- and 4,4'-dihydroxydiphenylmethanes were polymerized to give the polymer in high yields, whereas no polymerization of the 2,2'-isomer occurred. These data suggest that the radical transfer reaction between a phenoxy radical of the enzymatically polymerizable monomer and the enzymatically nonpolymerizable monomer frequently took place during the polymerization. Various 4,4'-dihydroxyphenyl compounds were also polymerized by peroxidase catalyst. The polymerization behaviors, and solubility and thermal properties of the resulting polymers strongly depended on the bridge structure as well as the enzyme origin. Polymers from dihydroxydiphenylmethanes showed relatively high thermal stability.

Artificial urushi

A new concept for the design and laccase-catalyzed preparation of "artificial urushi" from new urushiol analogues is described. The curing proceeded under mild reaction conditions to produce the very hard cross-linked film (artificial urushi) with a high gloss surface. A new cross-linkable polyphenol was synthesized by oxidative polymerization of cardanol, a phenol derivative from cashew-nut-shell liquid, by enzyme-related catalysts. The polyphenol was readily cured to produce the film (also artificial urushi) showing excellent dynamic viscoelasticity.