Gene/Protein Disease Symptom Drug Enzyme Compound
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Query: EC:1.12.7.2 (hydrogenase)
 3,522 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

Tritrichomonas foetus mutants resistant to metronidazole lack the hydrogenosomal enzymes pyruvate: ferredoxin oxidoreductase and hydrogenase. Hydrogenosomes of these organisms did not oxidize pyruvate or produce ATP in its presence. Elimination of hydrogenosomal metabolism of pyruvate was compensated by an increased rate of glycolysis. The resistant mutants excreted no organic acids and H2 as metabolic end products. Glycolysis of the resistant T. foetus KV1-1MR-100 can be summarized as 1 mol glucose----2 mol ethanol + 2 mol CO2. The parent strain KV1, excreting H2, CO2 and acidic end products, converted about 10% of glucose to ethanol. Both strains produced ethanol from pyruvate through the action of two cytoplasmic enzymes: pyruvate decarboxylase and alcohol dehydrogenase. The specific activity of the former enzyme, catalyzing nonoxidative decarboxylation of pyruvate to acetaldehyde, was nearly seven times higher in the resistant than in the parent strain. Alcohol dehydrogenase reducing acetaldehyde to ethanol was specific to NADPH; it catalyzed the reverse reaction only slowly, and displayed similar activities in both resistant and sensitive trichomonads. Development of anaerobic metronidazole resistance in T. foetus depended on the loss of pyruvate:ferredoxin oxidoreductase as well as on the ability to increase alcoholic fermentation.
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PMID:Metabolic differences between metronidazole resistant and susceptible strains of Tritrichomonas foetus. 637 46

Significant quantitative differences in end-product yields by two strains of Clostridium thermocellum and one strain of Thermoanaerobium brockii were observed during cellobiose fermentation. Most notably, the ethanol/H(2) and lactate/acetate ratios were drastically higher for T. brockii as compared with C. thermocellum strains LQRI and AS39. Exogenous H(2) addition (0.4 to 1.0 atm) during culture growth increased the ethanol/acetate ratio of both T. brockii and AS39 but had no effect on LQRI. All strains had an operative Embden-Meyerhof glycolytic pathway and displayed catabolic activities of fructose-1,6-diphosphate-activated lactate dehydrogenase, coenzyme A acetylating pyruvate and acetaldehyde dehydrogenase, hydrogenase, ethanol dehydrogenase, and acetate kinase. Enzyme kinetic properties (apparent K(m), V(max), and Q(10) values) and the specificity of electron donors/acceptors for different oxidoreductases involved in pyruvate conversion to fermentation products were compared in the three strains. Both species contained ferredoxin-linked pyruvate dehydrogenase and pyridine nucleotide oxidoreductases. Ferredoxin-nicotinamide adenine dinucleotide (NAD) reductase activity was significantly higher in T. brockii than in AS39 and was not detectable in LQRI. H(2) production and hydrogenase activity were inversely related to ferredoxin-NAD reductase activity in the three strains. Ferredoxin-NAD phosphate reductase activity was present in cell extracts of both species. Alcohol dehydrogenase activity in C. thermocellum was NAD dependent, unidirectional, and inhibited by low concentrations of NAD and ethanol. Ethanol dehydrogenase activity of T. brockii was both NAD and NADP linked, reversible, and not inhibited by low levels of reaction products. The high lactate yield of T. brockii correlated with increased fructose-1,6-diphosphate. The relation of catabolic enzyme activity and quantitative differences in intracellular electron flow and fermentation product yields of these thermophilic bacteria is discussed.
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PMID:Ethanol production by thermophilic bacteria: relationship between fermentation product yields of and catabolic enzyme activities in Clostridium thermocellum and Thermoanaerobium brockii. 743 65

Even though alcohol dependence is not often found in the elderly, alcohol consumption and alcohol abuse are both common. As the elderly also often take medication on a regular basis, this group is at particularly high risk for problems resulting from the concurrent use of these substances. Physical changes as a result of the aging process (e.g. reduction of body water, decrease of hepatic blood flow) and alcohol related diseases can influence the pharmacokinetics and pharmacodynamics of both ethanol as well as other drugs. Alcohol dehydrogenase (ADH), acetaldehydede hydrogenase (ALDH) and cytochrome P450 2E1 are the enzymes responsible for the metabolism of ethanol. These enzymes are also the sites of direct pharmacological interaction between ethanol and other drugs, however, altered effects of medication can also be caused by ethanol adding to or reducing the drug's effect. Although some of these effects result from heavy use of alcohol, others can also occur with moderate use. Interactions have most frequently been described for analgetics, psychopharmacologically active drugs, antihistamines, anticoagulants antihypertensive drugs and antibiotics.
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PMID:[Possible interaction between ethanol and drugs and their significance for drug therapy in the elderly]. 1143 25

End-product synthesis and enzyme activities involved in pyruvate catabolism, H(2) synthesis, and ethanol production in mid-log (OD(600) approximately 0.25), early stationary (OD(600) approximately 0.5), and stationary phase (OD(600) approximately 0.7) cell extracts were determined in Clostridium thermocellum ATCC 27405 grown in batch cultures on cellobiose. Carbon dioxide, hydrogen, ethanol, acetate and formate were major end-products and their production paralleled growth and cellobiose consumption. Lactate dehydrogenase, pyruvate:formate lyase, pyruvate:ferredoxin oxidoreductase, methyl viologen-dependant hydrogenase, ferredoxin-dependant hydrogenase, NADH-dependant hydrogenase, NADPH-dependant hydrogenase, NADH-dependant acetaldehyde dehydrogenase, NADH-dependant alcohol dehydogenase, and NADPH-dependant alcohol dehydrogenase activities were detected in all extracts, while pyruate dehydrogenase and formate dehydrogenase activities were not detected. All hydrogenase activities decreased (2-12-fold) as growth progressed from early exponential to stationary phase. Alcohol dehydrogenase activities fluctuated only marginally (<45%), while lactate dehydrogenase, pyruvate:formate lyase, and pyruvate:ferredoxin oxidoreductase remained constant in all cell extracts. We have proposed a pathway involved in pyruvate catabolism and end-product formation based on enzyme activity profiles in conjunction with bioinformatics analysis.
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PMID:Growth phase-dependant enzyme profile of pyruvate catabolism and end-product formation in Clostridium thermocellum ATCC 27405. 1942 11