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1.
Lactate dehydrogenases at physiological concentrations are inhibited by high concentrations of pyruvate when the enzyme and the pyruvate are incubated in the presence of oxidized nicotinamide-adenine dinucleotide before assay. The inhibition is much more pronounced with the H-type than with the M-type lactate dehydrogenase. These results suggest that substrate inhibition may be operative in vivo. 相似文献
2.
Tyramine-H3: deaminated metabolites in neuroblastoma tumors and in continuous cell line of a neuroblastoma 总被引：2，自引：0，他引：2
Neuroblastoma tumors, as well as cultured cells of neuroblastoma, contain high monoamine oxidase activity. The major deaminated metabolite of tyramine-H(3) in the incubation mixtures with the tumors or with the cultured cells is p-hydroxyphenylacetaldehyde. Upon addition of reduced nicotinamide-adenine dinucleotide phosphate, the aldehyde was further metabolized by the reductive pathway to p-hydroxyphenylethanol, whereas upon addition of nicotinamide-adenine dinucleotide phosphate the aldehyde was only metabolized to a minor extent by the oxidative pathway to p-hydroxyphenylacetic acid. Aldehyde dehydrogenase activity is very low in the neuroblastoma tumors and in the cultured neuroblastoma cells. The generation of aldehydes and alcohols by the action of monoamine oxidase suggests that the deaminated metabolites of biogenic amines might exhibit some toxic effects in neuroblastoma patients. 相似文献
3.
D(-)-lactate dehydrogenase in lower fungi 总被引：1，自引：0，他引：1
A lactate dehydrogenase, specific for nicotinamide-adenine dinucleotide and D(-)-lactate, has been detected in extracts from two fungi of the order Leptomitales (Oomycetes). Several fungi of this order carry out a lactic acid fermentation under conditions of reduced oxygen tension. 相似文献
4.
The addition of glucose stimulated release of insulin from the isolated islet tissue of the toadfish incubated in vitro. Reduced nicotinamide-adenine dinucleotide also stimulated insulin release, whereas the oxidized form had no effect. Both oxidized and reduced nicotinamide-adenine dinucleatide phosphate stimulated insulin release, but the reduced form was significantly more effective. 相似文献
5.
A Bekierkunst 《Science (New York, N.Y.)》1966,152(721):525-526
There is a decrease in the content of nicotinamide-adenine dinucleotide of tubercle bacilli grown in the presence of isoniazid. In extracts of tubercle bacilli, the activity of nicotinamide-adenine dinucleotidase is nil or very small; after incubation with the drug the enzyme becomes active. Isoniazid also increases the activity of the enzyme after it is partially activated by heating. There may be a correlation between the capacity of isoniazid to activate the enzyme and the decrease in the dinucleotide content of the tubercle bacilli. 相似文献
6.
Reduced nicotinamide-adenine dinucleotide phosphate oxidase: activity enhanced by ethanol consumption 总被引：3，自引：0，他引：3
Prolonged consumption of ethanol enhances the activities of the hepatic microsomal ethanol oxidizing system and of reduced nicotinamide-adenine dinucleotide phosphate oxidase, but not of catalase. The oxidase-catalase system is not part of the microsomal ethanol oxidizing system since catalase inhibitors dissociate ethanol oxidation by the two pathways. Enhanced reduced nicotinamide-adenine dinucleotide phosphate oxidase activity may contribute to liver injury, possibly by favoring lipoperoxidation. 相似文献
7.
Lead effects on corn mitochondrial respiration 总被引：4，自引：0，他引：4
Oxidation of exogenous nicotinamide-adenine dinucleotide and succinate by corn mitochondria was measured as a function of lead chloride concentration. Lead chloride (50 to 62 micromoles per liter) stimulated oxidation of exogenous reduced nicotinamide-adenine dinucleotide by 174 to 640 percent depending on the reaction mediums, whereas lead chloride (12.5 micromoles per liter) inhibited succinate oxidation by more than 80 percent. When inorganic phosphate was included in reaction mediums the subsequent addition of lead was without effect due to the low solubility of lead phosphate. If addition of lead was followed by addition of phosphate the inhibition of succinate oxidation by lead was released, but there was no reduction in the stimulation of oxidation of reduced nicotinamide-adenine dinucleotide by lead. The effects of lead on plant growth might be accentuated under conditions of phosphate deficiency. 相似文献
8.
Deficiency of reduced nicotinamide-adenine dinucleotide oxidase in chronic granulomatous disease 总被引：25，自引：0，他引：25
Reduced nicotinamide-adenine dinucleotide oxidase of normal human polymorphonuclear leukocytes has properties that would qualify it as the enzyme responsible for the respiratory burst during phagocytosis. The enzyme was deficient in leukocytes of five patients with chronic granulomatous disease. This lack of adequate reduced nicotinamide-adenine dinucleotide oxidase could be the basis for the metabolic abnormalities characteristic of these leukocytes and for their diminished bactericidal activity. 相似文献
9.
Hexokinase isoenzymes in human erythrocytes 总被引：4，自引：0，他引：4
The electrophoretic mobility of hexokinase from human erythrocytes and other tissues was studied with a new method that depends on the fluorescence of reduced nicotinamide-adenine dinucleotide phosphate for detecting enzyme activity on starch gel. The hexokinase of cord-blood erythrocytes has slightly different electrophoretic properties from that of adult red cells. Type I enzyme is split into type I(A) and type I(F); the latter is more intense in cord blood; in hemolyzates of adult blood, the activity of the two bands is usually about equal. No type II enzyme was found in cord blood. The double type I band was present in red cells from adult rabbits. 相似文献
10.
D L Gutnick P J Dunphy H Sakamoto P G Phillips A F Brodie 《Science (New York, N.Y.)》1967,158(807):1469-1471
Synthetic phylloquinone was resolved into cis and trans isomers by thin-layer chromatography. The two isomers had identical ultraviolet spectra characteristic of vitamin K(1) and were differentiated by nuclear-magnetic-resonance spectroscopy on the basis of the displacement of the peak corresponding to the olefinic methyl group in the naphthoquinone side chain. Studies on the restoration of electron transport coupled to phosphorylation in irradiated preparations of Mycobacterium phlei showed that only the trans isomer was active with substrates linked to nicotinamide-adenine dinucleotide. The purified trans phylloquinone was enzymatically converted to the cis isomer. Under similar conditions, cis vitamin K(1) gave rise to the trans-naphthoquinone. The natural naphthoquinone of M. phlei vitamin MK(9)(II-H) was similarly resolved into cis and trans isomers. 相似文献
11.
Hydroxylation of rotenone in vitro in the enzyme system composed of microsomes and reduced nicotinamide-adenine dinucleotide phosphate, and in living mice and houseflies, yields products tentatively identified as rotenolone I; rotenolone II; 8'-hydroxyrotenone; 6',7'-dihydro-6',7'-dihydroxyrotenone; two rotenolones of each of the last-mentioned two compounds; and uncharacterized polar materials. The toxicity of certain of these rotenoids to mice is of the same order as that of rotenone. 相似文献
12.
Force, shortening, and work in muscular contraction: relative contributions to overall energy utilization 总被引：2，自引：0，他引：2
The amounts of energy used during muscular contraction under different loads have been compared by measurement of the total amount of disturbance of the concentration of reduced nicotinamide-adenine dinucleotide during the period of oxidative recovery. The results are in quantitative agreement with the concept that three parameters determine the energy utilization: namely the time-integral of the force development, the time-integral of the shortening process, and the mechanical work. 相似文献
13.
Lustbader JW Cirilli M Lin C Xu HW Takuma K Wang N Caspersen C Chen X Pollak S Chaney M Trinchese F Liu S Gunn-Moore F Lue LF Walker DG Kuppusamy P Zewier ZL Arancio O Stern D Yan SS Wu H 《Science (New York, N.Y.)》2004,304(5669):448-452
Mitochondrial dysfunction is a hallmark of beta-amyloid (Abeta)-induced neuronal toxicity in Alzheimer's disease (AD). Here, we demonstrate that Abeta-binding alcohol dehydrogenase (ABAD) is a direct molecular link from Abeta to mitochondrial toxicity. Abeta interacts with ABAD in the mitochondria of AD patients and transgenic mice. The crystal structure of Abeta-bound ABAD shows substantial deformation of the active site that prevents nicotinamide adenine dinucleotide (NAD) binding. An ABAD peptide specifically inhibits ABAD-Abeta interaction and suppresses Abeta-induced apoptosis and free-radical generation in neurons. Transgenic mice overexpressing ABAD in an Abeta-rich environment manifest exaggerated neuronal oxidative stress and impaired memory. These data suggest that the ABAD-Abeta interaction may be a therapeutic target in AD. 相似文献
14.
Methylene-C14-dioxyphenyl compounds: metabolism in relation to their synergistic action 总被引：1，自引：0，他引：1
J E Casida J L Engel E G Essac F X Kamienski S Kuwatsuka 《Science (New York, N.Y.)》1966,153(740):1130-1133
The methylene-C(14) group is hydroxylated yielding formate-C(14) in the microsome-reduced nicotinamide-adenine dinucleotide phosphate system in vitro and yielding expired C(14)O(2), in living mice and houseflies. Methylenedioxyphenyl compounds apparently serve as alternate substrates for this enzymatic hydroxylation system of microsomes, and thus reduce the rate of metabolism and prolong the action of certain drugs and insecticide chemicals. 相似文献
15.
Characterization of an extremely large, ligand-induced conformational change in plasminogen 总被引：8，自引：0，他引：8
Native human plasminogen has a radius of gyration of 39 angstroms. Upon occupation of a weak lysine binding site, the radius of gyration increases to 56 angstroms, an extremely large ligand-induced conformational change. There are no intermediate conformational states between the closed and open form. The conformational chang is not accompanied by a change in secondary structure, hence the closed conformation is formed by interaction between domains that is abolished upon conversion to the open form. This reversible change in conformation, in which the shape of the protein changes from that best described by a prolate ellipsoid to a flexible structure best described by a Debye random coil, is physiologically relevant because a weak lysine binding site regulates the activation of plasminogen. 相似文献
16.
Pyrazole (4 millimoles per kilogram or 272 milligrams per kilogram of body weight), given to fasted rats 10 minutes before gavage with ethanol (4 grams per kilogram), completely prevented both the disappearance of ethanol from the blood over a 16-hour period and the ethanol-induced reduction in the ratio of oxidized to reduced hepatic nicotinamide-adenine dinucleotide. However, it did not affect the accumulation of triglycerides in the liver after the administration of ethanol. These results indicate that metabolism of ethanol is not required for production of fatty liver by a single, large dose of ethanol. 相似文献
17.
A unique form of lactate dehydrogenase was observed in the starch-gel electrophoretic patterns of adult human testes. It was present in sperm, but absent in prepubertal testes. Its electrophoretic mobility, heat stability, kinetic behavior with pyridine nucleotide analogs, and chromatographic characteristics on diethylaminoethyl cellulose were intermediate to those observed for lactate dehydrogenase isozymes 3 and 4. 相似文献
18.
以杜仲一叶一心期幼叶为材料，提取总BNA，采用RT-PCR技术分离得到498bp核苷酸片段，此核苷酸片段与CenBank中的苹果树肉桂醇脱氢酶(CAD)基因序列有64．1％的同源性，与桉树mRNA CAD有63．9％的同源性。所克隆的cDND编码165个氨基酸残基，其序列与苹果树CAD相应片段有68．5％的同源性，与桉树mRNA CAD相应片段有66．1％的同源性。推测克隆的核香酸片段为杜仲CAD的基因片段。 相似文献
19.
Ethanol inhibition of vitamin A metabolism in the testes: possible mechanism for sterility in alcoholics 总被引：2，自引：0，他引：2
Vitanin A (retinol) is essential for spermatogenesis. Alcohol dehydrogenase, the enzyme responsible for ethanol metabolism, is also required for the conversion of retinol to bioactive retinal at the end organ site. Ethanol inhibits the oxidation of retinol by testicular homogenates containing alcohol dehydrogenase. Thus, a possible biochemnical mechanism for the sterility of chronic alcoholics is identified. 相似文献
20.
Alcohol, amines, and alkaloids: a possible biochemical basis for alcohol addiction 总被引：10，自引：0，他引：10
Tetrahydropapaveroline is a benzyltetrahydroisoquinoline alkaloidderivative of the biogenic amine, dopnmine. Alcohol, by way of its primary metabolite, acetaldehyde, competitively inhibits nicotinamide-adenine Sinucleotide-linked aldehyde dehydrogenase and augments the formation of tetrahydropapaveroline in vitro. The limited capacity of brain to oxidize aldehydes may be of pharmacological importance because it facilitates the production of tetrahydropapaveroline in the presence of drugs which inhibit this enzyme. 相似文献