Dehydrogenase activity determination with

Oxidation of kerosene (fuel oil no. 1) and diesel fuel (fuel oil no. 2) by soil microbes, as determined by dehydrogenase activity, increased with increasing loading rates for both fuel oils (up to 60% w/w oil/dry soil) for up to 7 days of incubation but decreased thereafter. Dehydrogenase activity in soil treated with diesel fuel was almost twice that of soils treated with kerosene (56 and 32 g formazan/g soil/24 hours, respectively) (Frankenberger and Johanson 1982). 

Wu, C.-Y., Chen, S.-T., Choiu, S.-H. Wang, K.T. (1992). Kinetic analysis of duck e-crystallin with lactate dehydrogenase activity determination of kinetic constants and comparison of substrate specificity. Biochem. Biophys. Res. Common., 186, 874-80. 

Reaction 4 depends upon the operation of a DPN-dependent, lipoic acid dehydrogenase. A protein fraction has been obtained from E. coli which exhibits this property. Measurement of lipoic acid dehydrogenase activity directly with DPN+ and reduced lipoic acid as reductant or reoxidation of DPNH with a-lipoic acid as oxidant was not particularly successful. However, lipoic acid dehydrogenase activity could readily be determined by linking it with lactic acid dehydrogenase in the presence of pyruvate and catalytic amounts of DPN, by measuring the residual —SH groups. 

Because the metabolism of DEHP was catalyzed by so many fractions of the trout liver homogenate, these fractions were characterized by measurement of marker enzymes to determine which organelles actually were responsible for the observed DEHP metabolism. Succinic dehydrogenase activity was used as a marker for mitochondria, whereas glucose-6-phosphatase was used as a marker for microsomes. The distribution of DEHP oxidase activity (production of polar metabolites 1 and 2 with added NADPH) and of DEHP esterase activity (production of monoester without added NADPH) were also determined. It was found (Figure 2) that the distribution of DEHP oxidase activity parallels the distribution of microsomal activity and the distribution of DEHP esterase activity parallels the distribution of microsomal activity, but is also present in the cytosol fraction. 

Di Paolo A, Danes R, Ciofl L et al. Improved analysis of 5-fluorouracil and 5,6-dihydro-5-fluorouracil by HPLC with diode array detection for determination of cellular dihydropyrimidine dehydrogenase activity and pharmacokinetic profiling. Ther DrugMonit 2QQ5,21.362-36%. 

The determination of OXPHOS activity is best made with the aid of spectrophoto-metric assays [55, 65]. Using a judicious set of electron donors and acceptors, it is possible to measure the activity of MRC complexes either isolated or in combination, as described below. Beside the residual activity of each complex, ratios of their respective activities are of fundamental importance. Indeed, the balance between complexes (the ratio between their activities) determines on the one hand the relative access of each dehydrogenase to the MRC, and on the other hand the amount of superoxides possibly escaping the chain [55]. It is therefore quite important to both analyze residual activities corrected for the variable amount of mitochondria using the citrate synthase as reference enzyme, and the various ratios inside the MRC [66,67]. It is also important to note that enzyme determination is (supposedly at least) done under maximal rate (Vmax) conditions only, often leaving aside any discrete anomalies possibly affecting affinity and regulatory properties. 

Having a lifetime of two weeks, the sensor was capable of determining NADH and succinate with a linear range up to 0.13 and 0.15 mmolA, respectively. Competitive inhibition of the mitochondrial succinate dehydrogenase activity by malonate resulted in a totally selective sensor for NADH.In this way the selectivity enhancement of HIS sensors by inhibition of interfering metabolic routes was demonstrated. 

Microtox Solid-phase test SDI Vibrio fischeri is added to a suspension of the test sample. Subsequently, the mixture is filtered using the device supplied with the kit, and the light emission of the supernatant is determined. The method is a further development of the acute luminescent bacteria test for aqueous samples. Contact test with Bacillus cereus DSM No. 351 Effects on the dehydrogenase activity of the test bacterium after an exposure time of 2 hours are investigated using resazurine reduction (Ronnpagel etal. 1995). 

Dooley, J. R, L. J. Turnquist, and L. Racich. 1979. Kinetic determination of serum sorbitol dehydrogenase activity with a centrifugal analyzer. Clinical Chemistry 25 2026-2029. 

K. A. Holm, Spectrophotometric Flow-Injection Determination of Cello-biose Dehydrogenase Activity in Fermentation Samples with 2,6-Di-chlorophenolindophenol. Anal. Chim. Acta, 188 (1986) 285. 

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