Methanol dehydrogenase kinetics

Frank, J., Dijkstra, M., Duine, J. A., and Balny, C., 1988, Kinetic and spectral studies on die redox forms of methanol dehydrogenase from Hyphomicrobium X. Eur. J. Biochem. 174 331n338. 

Harris, T. K., and Davidson, V. L., 1993a, A new kinetic model for the steady-state reactions of the quinoprotein methanol dehydrogenase from Paracoccus-denitrificans. Biochemistry 32 4362n4368. 

In addition to enzyme activity, the concentration of an nonelectroactive substrate can be determined electrochemically by this technique. By keeping the substrate (analyte) the limiting reagent, the amount of product produced is directly related to the initial concentration of substrate. Either kinetic or equilibrium measurements can be used. Typically an enzyme which produces NADH is used because NADH is readily detected electrochemically. Lactate has been detected using lactate dehydrogenase, and ethanol and methanol detected using alcohol dehydrogenase... 

Pocker Y, Li H. 1990. Kinetics and mechanism of methanol and formaldehyde interconversion and formaldehyde oxidation catalyzed by liver alcohol dehydrogenase. Adv Exp Med Biol 284 315-325. 

Ethanol is metabolized in a two step process (see figure below), according to zero order kinetics. As the drug passes through the liver, it is first dehydrated by alcohol dehydrogenase, forming acetaldehyde (which dissociates into methanol and formaldehyde, should the next metabolic step be inhibited). Acetaldehyde is then metabolized by aldehyde dehydrogenase into acetate, which may then enter the citric acid cycle. 

B. Pharmacokinetics. Methanol is readily absorbed and quickly distributed to the body water (Vd = 0.6 L/kg). It is not protein bound. It is metabolized slowly by alcohol dehydrogenase via zero-order kinetics, at a rate about one-tenth that of ethanol. The reported half-life ranges from 2 to 24 hours, depending on whether metabolism is blocked (eg, by ethanol or fomepizole). Only about 3% is excreted unchanged by the kidneys and less than 10-20% through the breath. 

Kato N, Sahm H, Wagner F (1979) Steady-state kinetics of formaldehyde dehydrogenase and formate dehydrogenase from a methanol-utilizing yeast, Candida boidinii. Biochim Biophys Acta Enzymol 566 12-20... 

The rate constant for the incorporation of lead into the cryptand (2,1,1) in methanol is unusually high and reflects the high selectivity of this ligand for over the alkaline-earth-metal ions. The kinetics of metal-loporphyrin formation have been reviewed with particular reference to the metal-ion-assisted mechanism, and the kinetics and mechanism of the recombination of Co ", Ni ", and Zn " with the metal-depleted catalytic site of horse liver alcohol dehydrogenase have been reported. ... 

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