Dehydrogenases proteins

The specific activity is die total activity of die fracdon divided by the total protein in die fracdon. This value gives an indication of die increase in purity attained during die course of the purification as die samples become enriched for xandiine dehydrogenase protein. 

Niederhut MS, Gibbons BJ, Perez-Miller S, Hurley TD. Three-dimensional structures of the three human class I alcohol dehydrogenases. Protein Sci 2001 10 697-706. 

RD Chen, JA Grobler, JH Hurley, AM Dean (1996). Second-site suppression of regulatory phosphorylation in Escherichia coli isocitrate dehydrogenase. Protein Sci 5 287-295, 1996. 

AM Dean, L Dvorak. The role of glutamate 87 in the kinetic mechanism of Thermus thermophilus isopropylmalate dehydrogenase. Protein Sci 4 2156-2167, 1995. 

Rao, A.V.S. and T. Ramasarma. 2000. NADH-dependent decavanadate reductase, an alternative activity of NADP-specihc isocitrate dehydrogenase protein. Biochim. Biophys. Acta 1474 321-330. 

Fig. 36. Absorption spectrum of partially purified a-glycerophosphate dehydrogenase, protein concentration 13 mg/ml. (O) Spectrum of oxidized enzyme. The difference spectra (shown in the insert) were recorded after the addition of a few granules of sodium hydrosulfite ( ) or 5 Mmoles substrate (O) iu a total volume of 0.2 ml. In the difference spectra, a decrease in optical density indicates bleaching. From Ringler (225).

Eszes, R. B. Sessions, R. L. Brady, Structural basis for altered activity of M- and H-isozyme forms of human lactate dehydrogenase, Proteins Struct., Puna., Genet., 43, 175-185 (2001). 

Fraction ChAc Lactate dehydrogenase Protein ChAc Lactate dehydrogenase... 

Feliciano PR, Cordeiro AT, Costa-Filho AJ et al. Cloning, expression, purification, and characterization of Leishmania major dihydroorotate dehydrogenase. Protein Expr Purif 2006. 

Djouadi F, et til. Bezafibrate increases veiy-long-chain acyl-CoA dehydrogenase protein and mRNA expression in deficient fibroblasts and is a potential therapy for fatty acid oxidation disorders. Hum Mol Genet. 2005 14(18) 2695-703. 

Acyl dehydrogenase protein of unknown function DUF35 1526523-1527299... 

When a standard, non-ranked POSSUM search is carried out with angular and mid-point tolerances of 35° and 50%, a total of 23 hits is achieved, these including all examples of the four t3rpes of dehydrogenase protein. Of the 23 hits, 21 are dehydrogenases and 13 of these are in the correct fold. 

The recent identification of 9-cw-retinol dehydrogenase in the mouse embryo reveals a pathway for 9-cw-RAs synthesis in this species [60]. This membrane-bound enzyme is able to oxidize 9-c/5-retinol into 9-c/5-retinaldehyde which can be subsequently oxidized to 9-cis-RA. The expression of this enzyme is temporally and spatially controlled during embryogenesis in parts of the nervous system, sensory organs, somites and myotomes, and several tissues of endoder-mal origin. Mertz et al. have also identified a stereospecific human enzyme that catalyzes 9-cis-retinol oxidation and is likewise a member of the short chain alcohol dehydrogenase protein family [61]. The mRNA for the protein is most abundant in human mammary tissues. 

P.J. Baker, K.L. Britton, PC. Engel, G.W. Farrants, K.S. Lilley, D.W. Rice, T.J. Stillman, Subunit assembly and active-site location in the structure of glutamate-dehydrogenase. Protein Struct. Fund Genet. 12 (1) (1992) 75-86. 

The importance of the ionic bonds in the thermostabilization was emphasized by Perutz (1978). From differences in rate of denaturation in mesophilic and thermophilic molecules, Perutz (1978) has evaluated the extrastabilization energy to be no more than 2 kcal/mole in ferredoxin and 5-10 kcal/mole in glyceraldehyde-3-phosphate dehydrogenase. Proteins from thermophilic organisms offer a very good example, allowing one to... 

Schiff base fonnation, photochemistry, protein partitioning, catalysis by chymotrypsin, lipase, peroxidase, phosphatase, catalase and alcohol dehydrogenase. 

The Protein Data Bank PDB ID 1A71 Colby T D Bahnson B J Chin J K Klinman J P Goldstein B M Active Site Modifications m a Double Mutant of Liver Alcohol Dehydrogenase Structural Studies of Two Enzyme Ligand Com plexes To be published... 

Iron Sulfur Compounds. Many molecular compounds (18—20) are known in which iron is tetrahedraHy coordinated by a combination of thiolate and sulfide donors. Of the 10 or more stmcturaHy characterized classes of Fe—S compounds, the four shown in Figure 1 are known to occur in proteins. The mononuclear iron site REPLACE occurs in the one-iron bacterial electron-transfer protein mbredoxin. The [2Fe—2S] (10) and [4Fe—4S] (12) cubane stmctures are found in the 2-, 4-, and 8-iron ferredoxins, which are also electron-transfer proteins. The [3Fe—4S] voided cubane stmcture (11) has been found in some ferredoxins and in the inactive form of aconitase, the enzyme which catalyzes the stereospecific hydration—rehydration of citrate to isocitrate in the Krebs cycle. In addition, enzymes are known that contain either other types of iron sulfur clusters or iron sulfur clusters that include other metals. Examples include nitrogenase, which reduces N2 to NH at a MoFe Sg homocitrate cluster carbon monoxide dehydrogenase, which assembles acetyl-coenzyme A (acetyl-CoA) at a FeNiS site and hydrogenases, which catalyze the reversible reduction of protons to hydrogen gas. 

Gofactors. Frequendy proteins exist in their native state in association with other nonprotein molecules or cofactors, which are cmcial to their function. These may be simple metal ions, such as Fe " in hemerythrin or Ca " in calmodulin a heme group, as for the globins nucleotides, as for dehydrogenases, etc. 

NAD and NADP are required as redox coen2ymes by a large number of enzymes and ia particular dehydrogenases (Fig. 6). NAD" is utilized ia the catabohe oxidations of carbohydrates, proteins, and fats, whereas NADPH2 is the coenzyme for anaboHc reactions and is used ia fats and steroid biosynthesis. NADP+ is also used ia the cataboHsm of carbohydrates (2). 

In contrast to the nicotinamide nucleotide dehydrogenases, the prosthetic groups FMN and FAD are firmly associated with the proteins, and the flavin groups are usually only separated from the apoen2yme (protein) by acid treatment in water. However, in several covalently bound flavoproteins, the enzyme and flavin coen2ymes are covalently affixed. In these cases, the flavin groups are isolated after the proteolytic digestion of the flavoproteins. 

Covalently Bound Flavins. The FAD prosthetic group in mammalian succinate dehydrogenase was found to be covalently affixed to protein at the 8 a-position through the linkage of 3-position of histidine (102,103). Since then, several covalently bound riboflavins (104,105) have been found successively from the en2ymes Hsted in Table 3. The biosynthetic mechanism, however, has not been clarified. 

U Ryde. Molecular dynamics simulations of alcohol dehydrogenase with a four- or five-coordinate catalytic zinc ion. Proteins 21 40-56, 1995. 

Figure 1.9 Examples of functionally important intrinsic metal atoms in proteins, (a) The di-iron center of the enzyme ribonucleotide reductase. Two iron atoms form a redox center that produces a free radical in a nearby tyrosine side chain. The iron atoms are bridged by a glutamic acid residue and a negatively charged oxygen atom called a p-oxo bridge. The coordination of the iron atoms is completed by histidine, aspartic acid, and glutamic acid side chains as well as water molecules, (b) The catalytically active zinc atom in the enzyme alcohol dehydrogenase. The zinc atom is coordinated to the protein by one histidine and two cysteine side chains. During catalysis zinc binds an alcohol molecule in a suitable position for hydride transfer to the coenzyme moiety, a nicotinamide, [(a) Adapted from P. Nordlund et al., Nature 345 593-598, 1990.)...

Figure 4.1 Alpha/beta domains are found in many proteins. They occur in different classes, two of which are shown here (a) a closed barrel exemplified by schematic and topological diagrams of the enzyme trlosephosphate isomerase and (b) an open twisted sheet with helices on both sides, as in the coenzymebinding domain of some dehydrogenases. Both classes are built up from p-a-p motifs that are linked such that the p strands are parallel. Rectangles represent a helices, and arrows represent p strands in the topological diagrams, [(a) Adapted from J. Richardson, (b) Adapted from B. Furugren.j...

ADH Horse liver alcohol dehydrogenase, an enzyme dimer of identical 374 amino acid polypeptide chains. The amino acid composition of ADH is reasonably representative of die norm for water-solnble proteins. 

Example of a Protein Purification Scheme Purification of the Enzyme Xanthine Dehydrogenase from a Eungus... 

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