Methanol oxidase

This enzyme [EC 1.1.3.13], also known as methanol oxidase and AOX, catalyzes the reaction of a primary alco-... 

Aston et al. (1984) devised a methanol sensor for use in drinking water treated by methylotrophic bacteria for nitrate removal. Methanol oxidase from Methylosimus trichosporium was immobilized on a carbon paste electrode containing l,l -dimethylferrocene. The measured signal was linearly dependent on methanol concentration in the range of 1 to 5 mg/1. The intermediate product of methanol oxidation to formate (formaldehyde) was indicated with half the sensitivity. The sensor was stable for only 3 h. 

Figure 2.10. The active site and its local environment for different catalytic systems. (A) The single monoatomic zeolitic cation site (Fe in ferrierite) (B) the single site enzyme and its local cavity which provide multiple points of additional contact (methanol oxidase) the ensemble of metal atoms, (C) site for Fe-catalyzed ammonia synthesis.

Diethylaminoethylcellulose has been used for the immobilization of methanol oxidase and D-glucose isomerase by physical adsorption. 

The current-voltage behavior of the biofuel cell at different external loads and at optimized concentrations of the oxidizer and fuel substrates are shown in Fig. 28(b). Up to 32 pW could be extracted at an external load of 3 kS2 (Fig. 28b, inset). The configuration of this biofuel cell represents a very general method for the development of future biofuel cell elements as it can be extended to other oxidative enzymes and fuel substrates, such as methanol oxidase or lactate oxidase and the respective alcohol or lactic acid fuel substances. 

On the base of alcohol oxidase and flavocytochrome b, the enzymatic kits for selective assay of ethanol, methanol, formaldehyde and L-lactate were developed. 

The alcohol tolerance of O2 reduction by bilirubin oxidase means that membraneless designs should be possible provided that the enzymes and mediators (if required) are immoblized at the electrodes. Minteer and co-workers have made use of NAD -dependent alcohol dehydrogenase enzymes trapped within a tetraaUcylammonium ion-exchanged Nafion film incorporating NAD+/NADH for oxidation of methanol or ethanol [Akers et al., 2005 Topcagic and Minteer, 2006]. The polymer is coated onto an electrode modified with polymethylene green, which acts as an electrocatalyst... 

Besides the standard vectors for constitutive and inducible expression of genes in P. pastoris, new expression vectors and promoters with new regulatory features allowing, for example, also methanol-free inducible high-level expression were discovered or developed by mutagenesis of the mostly used alcohol oxidase promoter Paoxi [87]. Thus, a new P. pastoris expression system became available, which is commercialized by the company VTU (AT). 

Kiess, M., Hecht, H.J. and Kalisz, H.M. (1998) Glucose oxidase from Penicillium amagasakiense primary structure and comparison with other glucose-methanol-choline (GMC) oxidoreductases. European Journal of Biochemistry, 252, 90-99. 

Isobe, K. and Nishise, H. (1994) Enzymic production of glyoxal from ethylene glycol using alcohol oxidase from methanol yeast. Bioscience Biotechnology and Biochemistry, 58 (1), 170-173. 

FIGURE 5.7. Effect of changing the cosubstrate and the pH on the kinetics of an homogeneous redox enzyme reaction as exemplified by the electrochemical oxidation of glucose by glucose oxidase mediated by one-electron redox cosubstrates, ferricinium methanol ( ), + ferricinium carboxylate ( ), and (dimethylammonio)ferricinium ( ). Variation of the rate constant, k3, with pH. Ionic strength, 0.1 M temperature 25°C. Adapted from Figure 3 in reference 11, with permission from the American Chemical Society. 

The ability of HRP to degrade the plant hormone indole-3-acetic acid (lAA) in the absence of hydrogen peroxide was noted as early as 1955 (136). Plant peroxidases are now known to be of major importance in the metabolism of lAA (137) (note that they are often referred to as indole acetic acid oxidases in the older literature). The mechanism of lAA oxidation by HRP C is complex and has been studied experimentally in great detail by several groups (23, 137). Reaction products include indole-3-methanol, indole-3-aldehyde, and 3-methylene oxin-dole, which is probably a nonenzymatic conversion product of indole-3-methylhydroperoxide. The most important developments in this area have been reviewed (23). 

A flavoprotein oxidase, which is also a methanol oxidizing enzyme, was inhibited by cyclopropanol 4 through the formation of a N-5 flavin adduct with a ring opened cyclopropyloxy radical [10]. 

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