Dehydrogenases, structure-activity correlation

Similarly, enzyme activity has been correlated to solvent polarity. Oxidation of cinnamyl alcohol by horse liver alcohol dehydrogenase (LADH) (pH 7.5) was observed in anhydrous hexane, methylene chloride and acetonitrile (Guinn et al., 1991). The oxidation rates were observed to increase as the dielectric constant decreased (Table 5). Electron paramagnetic spectroscopy (EPR) and two active site directed spin labels were used to examine the effect of solvent dielectric on structural stability. As the dielectric constant of the solvent decreased, the spectra broadened, indicative of an increase in rigidity or stability. 

When designing models of coenzymes it is important to examine the structure of the corresponding enzymes. The three-dimensional structure of horse liver alcohol dehydrogenase has been resolved at 0.24 nm resolution by the group of C. I. Branden from Uppsala (280) and has been correlated to a number of physical and chemical studies in solution. The active enzyme has a molecular weight of 80,000 and is a dimer of two identical subunits. 

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