Dehydrogenase activity

Oxidation of P-nicotinamide adenine dinucleotide (NADH) to NAD+ has attracted much interest from the viewpoint of its role in biosensors reactions. It has been reported that several quinone derivatives and polymerized redox dyes, such as phenoxazine and phenothiazine derivatives, possess catalytic activities for the oxidation of NADH and have been used for dehydrogenase biosensors development [1, 2]. Flavins (contain in chemical structure isoalloxazine ring) are the prosthetic groups responsible for NAD+/NADH conversion in the active sites of some dehydrogenase enzymes. Upon the electropolymerization of flavin derivatives, the effective catalysts of NAD+/NADH regeneration, which mimic the NADH-dehydrogenase activity, would be synthesized [3]. 

It may seem surprising that isocitrate dehydrogenase is strongly regulated, because it is not an apparent branch point within the TCA cycle. However, the citrate/isocitrate ratio controls the rate of production of cytosolic acetyl-CoA, because acetyl-CoA in the cytosol is derived from citrate exported from the mitochondrion. (Breakdown of cytosolic citrate produces oxaloacetate and acetyl-CoA, which can be used in a variety of biosynthetic processes.) Thus, isocitrate dehydrogenase activity in the mitochondrion favors catabolic TCA cycle activity over anabolic utilization of acetyl-CoA in the cytosol. 

Figure 11. (a) Succinate dehydrogenase activity in normal skeletal muscle, (b) Muscle from patient with complex 11 deficiency showing severely decreased succinate dehydrogenase activity. 

Fig. 30. Variation of alcohol dehydrogenase activity with number of passes through various pumps [42]...

Amador, E. Dorfman, L. E. and Wacker, W. E. C. Serum lactic dehydrogenase activity. An analytical assessment of current assays. Clin. Chem. (1963), , 391-399. 

Harvey, M. Measurement of erythocytes glucose-6-phosphate dehydrogenase activity with a centrifugal analyzer. Clin. Chem. (1975), 134-138. 

Can dehydrogenase active sites catalyze other types of 1,2-carbonyl additions ... 

These methods will also be useful in tackling longer-term projects that may involve carving out individual modules from large, multidomain assemblies and using dehydrogenase active sites to catalyze other types of carbonyl additions. 

ZellnerG, A Jargon (1997) Evidence fora tungsten-stimulated aldehyde dehydrogenase activity of ZJe MZ/ovZfcrZo simplex that oxidizes aliphatic and aromatic aldehydes Arch Microbiol 168 480-485. 

Althongh the prodnct from the transformation of toluene by mntants of Pseudomonas putida lacking dehydrogenase activity is the cis-2R,3S dihydrodiol, the cis-2S,3R dihydrodiol has been synthesized from 4-iodotoluene by a combination of microbiological and chemical reactions. P. putida strain UV4 was used to prepare both enantiomers of the di-dihydrodiol, and iodine was chemically removed nsing H2 -Pd/C. Incubation of the mixtnre of enantiomers with P. putida NCIMB 8859 selectively degraded the 2R,3S componnd to prodnce toluene cis-2S,3R dihydrodiol (Allen et al. 1995). 

Carbon monoxide dehydrogenase active site CO oxidation / CO, reduction... 

Buur A, N Mprk. (1992). Metabolism of testosterone during in vitro transport across Caco-2 cell monolayers Evidence for beta-hydroxysteroid dehydrogenase activity in differentiated Caco-2 cells. Pharm Res 9 1290-1294. 

Hafner, E.W., Holley, B.W., Holdom, K.S. et al. (1991) Branched-chain fatty acid requirement for avermectin production by a mutant of Streptomyces avermitilis lacking branched-chain 2-oxo acid dehydrogenase activity. Journal of Antibiotics (Tokyo), 44, 349-356. 

The chain shortening pathway has not been characterized in detail at the enzymatic level in insects. It presumably is similar to the characterized pathway as it occurs in vertebrates. These enzymes are a partial P-oxidation pathway located in peroxisomes [29]. The key enzymes involved are an acyl-CoA oxidase (a multifunctional protein containing enoyl-CoA hydratase and 3-hy-droxyacyl-CoA dehydrogenase activities) and a 3-oxoacyl-CoA thiolase [30]. These enzymes act in concert to chain shorten acyl-CoAs by removing an acetyl group. A considerable amount of evidence in a number of moths has accumulated to indicate that limited chain shortening occurs in a variety of pheromone biosynthetic pathways. 

Ho DH, Townsend L, Luna MA et al. Distribution and inhibition of dihydrouracil dehydrogenase activities in human tissues using 5-fluorouracil as a substrate. Anticancer Res 1986 6 781-784. 

Lu Z, Zhang R, Diasio RB. Dihydropyrimidine dehydrogenase activity in human peripheral blood mononuclear cells and liver population characteristics, newly identified deficient patients, and clinical implication in 5-fluorouracil chemotherapy. Cancer Res 1993 53 5433-5438. 

Stephan F, Etienne MC, Wallays C et al. Depressed hepatic dihydropyrimidine dehydrogenase activity and fluorouracil-related toxicities. Am J Med 1995 99 685-688. 

Fleming RA, Milano GA, Gaspard MH, et al. Dihydropyrimidine dehydrogenase activity in cancer patients. Eur J Cancer 1993 29A 740-744. 

Van Kuilenburg AB, Vreken P, Beex LV et al. Severe 5-fluorouracil toxicity caused by reduced dihydropyrimidine dehydrogenase activity due to heterozygosity for a G ->A point mutation. J Inherit Metab Dis 1998 21 280-284. 

Grem JL, Yee LK, Venzon DJ et al. Inter-and intraindividual variation in dihydropyrimidine dehydrogenase activity in pe-... 

Chazal M, Etienne MC, Renee N et al. Link between dihydropyrimidine dehydrogenase activity in peripheral blood mononuclear cells and liver. Clin Cancer Res 1996 2 507-510. 

Gautier S.M., Blum L.J., Coulet P.R., Dehydrogenase activity monitoring by flow injection analysis combined with luminescence based fibre-optic sensors, Anal. Chim. Acta 1992 266 331-338. 

Fig. 1. Dynamics of urease, acid phosphatase and dehydrogenase activity in soil under Cd pollution (Soil urease activity is expressed as mg NH3-N g 1 dry soil 24 h-1, Soil phosphatase activity is expressed as the mg phenol produced g-1 dry soil 24 h 1, Soil dehydrogenase activity is expressed as mgTPF g-1 dry soil 24 h 1, from Akmal et al. 2005b).

Klee, C. B. and Sokoloff, L. Changes in D(-)-(J-hydroxybu-tyric dehydrogenase activity during brain maturation in the rat./. Biol. Chem. 242 3880-3883. 1967. 

---