Cytochrome methanol dehydrogenase

This chapter will review the general features of the enzymology of methanol dehydrogenase, its structure as determined by X-ray crystallography, the properties of the prosthetic group (PQQ), the mechanism of its reduction by substrate, its oxidation by its specific cytochrome electron acceptor, and processes involved in its synthesis. 

Alefounder, P. R., and Ferguson, S. J., 1981, A periplasmic location for methanol dehydrogenase from Paracoccus denitrificans implications for proton pumping by cytochrome aa3. Biochem. Biophys. Res. Comm. 98 778n784. 

Chan, H. T. C., and Anthony, C., 1991, The interaction of methanol dehydrogenase and cytochrome cl in an acidophilic methylotroph, Acetobacter methanolicus. Biochem. J. 280 139nl46. 

Dijkstra, M., Frank, J., and Duine. J. A., 1989, Studies on electron transfer from methanol dehydrogenase to cytochrome cL, both purified from Hyphomicrobium X. Biochem. J. 257 87ii94. 

Harris, T. K., and Davidson, V. L., 1993b, Binding and electron transfer reactions between methanol dehydrogenase and its physiologic electron acceptor cytochrome C55jjOa kinetic and thermodynamic analysis. Biochemistry 32 14145nl4150. 

Harris,T. K., Davidson,V. L, Chen, L., Mathews, F. S., and Xia, Z-H., 1994, Ionic strength dependence of the reaction between methanol dehydrogenase and cytochrome c-551i Evidence of conformationally coupled electron transfer. Biochemistry 33 12600nl2608. 

The methanotrophic bacteria have one known pathway for aerobic methane oxidation to CO2 31, 42,123). MMO catalyzes the first energetically difficult step in the formation of methanol from methane. The second step is catalyzed by methanol dehydrogenase (with a PQQ cofactor) and results in formation of formaldehyde, which is then converted by formaldehyde dehydrogenase (with no known cofactor) to formate. Finally, carbon dioxide is produced by formate dehydrogenase (with five different iron-sulfur clusters, a Mo-pterin cofactor, and an unusual flavin) 31, 42, 123). MMOs have a unique ability to oxidize a broad range 31,42,128,129) of hydrocarbons in addition to methane. One other system with a similar broad substrate utilization is the monoheme cytochrome P450 family, but in this case different isozymes show different specific activities (31). For soluble MMO, one single... 

Xia ZX, Dai WW, He YN, White SA, Mathews FS, Davidson VL (2003) X-ray structure of methanol dehydrogenase from Paracoccus denitrificans and molecular modeling of its interactions with cytochrome C-551L J Biol Inotg Chem 8 843-854... 

Porous chitosan has recently been evaluated as a protein delivery system by Cardinal et al. (1990). Sustained release was demonstrated for bovine growth hormone, alkaline phosphatase, and BSA. Treatment of dried particles of chitosan with methanol for brief periods extended release duration, with a 10-min treatment increasing the time required for 50% release of BSA from <1 day to 2 weeks. Jamas et al. (1991) have documented preparations of P-glucan microparticles, where time to 50% release ranged from 30min for cytochrome c (MW 14,000) to 200 min for alcohol dehydrogenase (MW 150,000). 

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