Aniline enzymatic

Figure 8.1 Two different pathways for aniline enzymatic polymerization. On top, traditional ortho-coupling. Below, template-assisted enzymatic polymerization of aniline. (Reproduced with permission from [15]. Copyright (1998) American Chemical Society).

Tamaoku and colleagues presented an efficient enzymatic photometric determination of hydrogen peroxide ffiat is essentially a color reaction resulting from the oxidative condensation of A/-ethyl-A/-(2-hydroxy-3-sulfopropyl)aniline derivatives wiffi 4-aminoantipyrine in the presence of hydrogen peroxide and peroxidase (82CPB2492). A similar calorimetric detection of hydrogen peroxide has been patented (83GEP3301470). 

Enzymes are generally classified into six groups. Table 1 shows typical polymers produced with catalysis by respective enzymes. The target macromolecules for the enzymatic polymerization have been polysaccharides, poly(amino acid)s, polyesters, polycarbonates, phenolic polymers, poly(aniline)s, vinyl polymers, etc. In the standpoint of potential industrial applications, this chapter deals with recent topics on enzymatic synthesis of polyesters and phenolic polymers by using enzymes as catalyst. 

The oxidative polymerization of phenols and anilines by enzymatic and chemical methods is an important method for synthesizing polyphenols50 and polyanilines51 in material research. Such polymerizations are often carried out in aqueous conditions. 

Because practically all aromatic organic pollutants that release phenols or anilines in the course of their degradation could bind HS through enzymatic catalysis, methods employing enzyme-catalyzed polymerization reactions minimizing their presence by partial removal in aquatic and terrestrial environments might be utilized in pollution control. This can have a remarkable effect in environmental engineering practice. 

Fig. 1 Influence of aniline to template ratio on conductivity for enzymatic PANI/DODD (diamonds) and enzymatic PANI/DBSA (squares). (Reprinted with permission from Rumbau et al. [38], (g) 2007, Elsevier)...

Guo ZW, Ruegger H, Kissner R, Ishikawa T, Willeke M, Walde P (2009) Vesicles as soft templates for the enzymatic polymerization of aniline. Langmuir 25(19) 11390-11405... 

Table 3.26 lists illustrative examples of cleavage reactions of support-bound N-aryl-carbamates, anilides, and /V-arylsulfonamidcs. /V-Arylcarbamatcs are more susceptible to attack by nucleophiles than /V-alkylcarbamates, and, if strong bases or nucleophiles are to be used in a reaction sequence, it might be a better choice to link the aniline to the support as an /V-bcnzyl derivative. Entry 7 (Table 3.26) is an example of a safety-catch linker for anilines, in which activation is achieved by enzymatic hydrolysis of a phenylacetamide to liberate a primary amine, which then cleaves the anilide. 

Some of the reactions of PO3- parallel enzymatic reactions promoted by adenosine triphosphate (ATP). Pyruvate kinase catalyzes the equilibration of ATP and pyruvate with adenosine diphosphate (ADP) and phosphoenol pyruvate (11,12). In a formal sense, this reaction resembles the preparations of enol phosphate (eqs. 6 and 7). Cytidine triphosphate synthetase catalyzes the reaction of uridine triphosphate with ammonia to yield cytidine triphosphate (13). In a formal sense, this reaction resembles the replacement of the ester carbonyl group of ethyl acetate by the nitrogen of aniline (eq. 8). 

Klibanov AM, Alberti BN, Morris ED, Felshin LM. Enzymatic removal of toxic phenols and anilines from waste waters. J Appl Biochem 1980 2 414-421. 

Nagarajan R, Samuelson L, Tripathy S, Liu W, Kumar J, Bruno F (2003) Enzymatic polymerization of aniline or phenols around a template. US Patent 6569651... 

CPH-treatment of rats (1200 mg/kg/d for 2 d) induced the enzymatic activities of other renal cortical drug-metabolizing enzymes such as 7-ethoxy-couma-rine-O-deethylase and cytosolic GSH-S-transferase whereas the enzymatic activities of aniline hydroxylase and aminopyrine-N-demethylase were simultaneously decreased or remained unchanged, respectively (Table 1) [74]. Treatment of male and female rats with cephaloridine (750 mg/kg/d) for two weeks to three... 

A. M. Klibanov, B.N. Alberti, E.D. Mortis, and L. M. Felshin, "Enzymatic Removal of Toxic Phenols and Anilines from Waste Waters , Journal of Applied Biochemistry, v.2, 1980, p. 414-21. 

In living cells, various oxidoreductases play an important role in maintaining the metabolism of living systems. Most of oxidoreductases contain low-valent metals as the catalytic center. In vitro enzymatic oxidoreductions have afforded functional organic materials.1 Recently, some oxidoreductases such as peroxidase, laccase, and bilirubin oxidase have received much attention as catalyst for the oxidative polymerizations of phenol and aniline derivatives to produce novel polyaromatics. 

The addition of templates enabled the enzymatic production of conducting polymers with well-defined structure.67 In using sulfonated polystyrene (SPS) as a template, the resulting polymer was soluble in water and the conductivity reached 5 x 10 3 S/cm without doping. Besides SPS, a strong acid surfactant (sodium dodecylbenzenesulfonic acid) or poly(vi-nylphosphonic acid) provided a suitable local template environment leading to the formation of conducting poly aniline. 

The enzymatic treatment of chitosan in the presence of tyrosinase and phenol derivatives produced new materials based on chitosan.91 During the reaction, unstable o-quinones were formed, followed by the reaction with the amino group of chitosan to give the modified chitosan. The tyrosinase-catalyzed modification of chitosan with phenols dramatically altered rheological and surface properties of chitosan. The modification with chlorogenic acid onto chitosan conferred the water solubility of chitosan under basic conditions.92 A new water-resistant adhesive was developed by the tyrosinase-catalyzed reaction of 3,4-dihydroxyphenethylamine and chitosan.93 Poly(4-hydroxystyrene) was modified with aniline by using tyrosinase catalyst.94 The incorporated ratio of aniline into the polymer was very low (1.3%). 

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