Alcohol dehydrogenase, protection from

Another problem with small models is that molecules from the solution (e.g. water) may come in and stabilise tetragonal structures and higher coordination numbers [224]. It is illustrative that very few inorganic con5)lexes reproduce the properties of the blue copper proteins [66,67], whereas typical blue-copper sites have been constructed in several proteins and peptides by metal substitution, e.g. insulin, alcohol dehydrogenase, and superoxide dismutase [66]. This shows that the problem is more related to protection from water and dimer formation than to strain. 

It is interesting to note that the effect of the two forms of the coenzyme on the H-D exchange of yeast alcohol dehydrogenase followed the order of their effectiveness in protecting the enzyme from denaturation by urea (Sekuzu et al., 1957). 

E.Racker Dr. Barron, Ileft it quite open what the quantitative role of glutathione in plant respiration is. I just pointed out that GSH-linked enzymes for a hydrogen transfer from substrate to oxygen occur in some plants. In regard to your comments about the role of SH groups in alcohol dehydrogenase, I would like to point out that yeast alcohol dehydrogenase is very sensitive to iodoacetate and can be protected b the addition of DPN. 

RBP plays a number of important physiological roles. First, RBP serves to solubilize the water-insoluble retinol molecule and to provide a vehicle to transport retinol from the liver to peripheral tissues. Second, RBP also serves to protect the reactive retinol molecule from oxidative damage while it is transported in plasma. Thus, free retinol is unstable in aqueous dispersion, whereas the retinol in the retinol-RBP complex is quite stable in stored plasma for weeks to months. Retinol bound to RBP is unavailable for oxidation by liver alcohol dehydrogenase, in contrast to retinol more weakly (and less specifically) com-plexed with either bovine serum albumin or B-lactoglobulin (Futterman and Heller, 1972). 

Fig. 10.9 Schematic representation of molecular machineries that confer acetic acid resistance in Acetobacter and Gluconacetobacter. (Schematic diagram quoted from Nakano and Fukaya 2008) THBH and phosphatidylcholine on the membrane and polysaccharide on the surface of the cells are suggested to be involved in acetic acid resistance. Acetic acid, which penetrates into the cytoplasm, is assumed to be metabolized through the TCA cycle by the actions of enzymes typical for AAB. Furthermore, intracellular acetic acid is possibly pumped out by a putative ABC transporter and proton motive force-dependent efflux pump using energy produced by ethanol oxidation or acetic acid overoxidation. Intracellular cytosolic enzymes are intrinsically resistant to low pH and are protected against denaturation by stress proteins such as molecular chaperones. ADH membrane-bound alcohol dehydrogenase, ALDH membrane-bound aldehyde dehydrogenase, CS citrate synthase, ACN aconitase, PC phosphatidylcholine...

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