Gene/Protein Disease Symptom Drug Enzyme Compound
Pivot Concepts: Gene/Protein Disease Symptom Drug Enzyme Compound   Target Concepts: Gene/Protein Disease Symptom Drug Enzyme Compound

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Query: EC:1.1.1.1 (alcohol dehydrogenase)
9,284 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

Some physical and chemical properties of the monomeric NADP+-dependent aldehyde reductase (previously called TPN-L-hexonate dehydrogenase or D-glucuronate reductase) from pig kidney have been examined. The amino acid composition has been determined. Four of the five thiol groups react with p-mercuribenzoate at pH 7, with no resulting loss of catalytic activity. High concentrations of p-mercuribenzoate cause complete enzyme inhibition, which can be partly reversed by addition of aldehyde reductase is low (9%, estimated from the ellipticity at 208 nm), and 70 to 80% of the tyrosine and tryptophan residues aare buried within the molecule. One molecule of NADPH binds to the enzyme (Kp equal 25 muM), causing a blue shift and enhancement of the coenzyme fluorescence, and suggesting that the environment of the active site is hydrophobic. In the reduction of D-glyceraldehyde, catalyzed by aldehyde reductase, the pro-4R "A" hydrogen of NADPH attacks the re face of the carbonyl group. This stereospecificity is the same as in the reductions of D-glyceraldehyde and acetaldehyde effected by rabbit muscle dehydrogenase and liver alcohol dehydrogenase, respectively.
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PMID:Properties of the nicotinamide adenine dinucleotide phosphate-dependent aldehyde reductase from pig kidney. Amino acid composition, reactivity of cysteinyl residues, and stereochemistry of D-glyceraldehyde reduction. 23 31

The effect of long-term administration of phenobarbital (PB) or barbital for five weeks on brain aldehyde reductase (A1R) and aldehyde dehydrogenase (A1DH) activities in the rat was studied. Mitochondrial (m)-A1DH and NADH-dependent A1R activities were significantly increased over control values after five-week treatment with PB or barbital, while no significant alteration of supernatant (s)-A1DH and NADPH-dependent A1R activities was observed under the same condition. Increase in m-A1DH activity by the treatment with barbiturates was recovered to the control level, however, increased activity of NADH-dependent A1R was maintained even after the cessation of the treatment. In groups of rats pretreated with barbiturates for five weeks, no animals were induced to sleep after intracerebroventricular injection of PB, and this finding strongly suggests the decrease in sensitivity of rats to barbiturates.
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PMID:Induction of NADH-dependent aldehyde reductase by successive administration of barbiturates in rat brain. 46 55

The metabolism of 3H-norepinephrine (3H-NE) released by different frequencies of nerve stimulation was studied in the perfused cat spleen after labeling the endogenous stores with (-)-3H-NE. For a wide range of frequencies of stimulation, unmetabolized 3H-NE represented between 50 and 60% of the total increase in outflow of radioactivity elicited by nerve stimulation. The deaminated glycol, 3,4-dihydroxyphenylglycol (3H-DOPEG), was the main metabolite of 3H-NE released by nerve stimulation. When the increase in outflow of radioactivity was analyzed for the samples collected during nerve stimulation, there was a progressive decrease in the fraction of 3H-NE released which was collected as 3H-metabolites as the frequency of stimulation was increased from 0.5 to 5 Hz. For the samples collected in the poststimulation period, there was no frequency dependence in the metabolism of the released transmitter: approximately 75% of the total overflow of radioactivity was accounted for by the 3H-NE metabolites, particularly 3H-DOPEG. The time course of the metabolism of 3H-NE released by nerve stimulation revealed that 3H-DOPEG formation was rather small during stimulation and that it increased sharply in the poststimulation samples. The selective increase in 3H-DOPEG formation in the poststimulation period is compatible with the view that neuronal uptake of the released transmitter might be increased immediately after nerve stimulation. Inhibition of neuronal uptake by cocaine or by phenoxybenzamine prevented 3H-DOPEG formation from 3H-NE released by nerve stimulation. Yet, in the presence of cocaine, the fractional release of total radioactivity per shock was not increased at either 1, 5 or 30 Hz. These results support the view that a large fraction of the 3H-NE released by stimulation which is recaptured by nerve endings is metabolized to 3H-DOPEG rather than stored for subsequent reuse. The extensive conversion to 3H-DOPEG of 3H-NE released by nerve stimulation suggests that there may be a difference between the process of neuronal uptake under resting conditions and that which operates under conditions of nerve stimulation. This difference may be related to the concentration of the transmitter achieved in the synaptic gap in each experimental condition. Under resting conditions and during perfusion with low concentrations of NE, neuronal uptake in the perfused cat spleen is coupled with vesicular storage. On the other hand, when the extracellular concentration of NE is increased as a result of nerve stimulation, neuronal uptake of NE appears to be coupled with presynaptic metabolism through monoamine oxidase and aldehyde reductase.
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PMID:Influence of the frequency of nerve stimulation on the metabolism of 3H-norepinephrine released from the perfused cat spleen: differences observed during and after the period of stimulation. 93 13

A barbiturate-sensitive aldehyde reductase was purified to homogeneity from rat liver and shown to metabolize the cancer-chemotherapeutic antibiotic daunorubicin. The aldehyde reductase may have important roles in the metabolism of exogeneous drugs as well as the aldehyde derivatives of the biogenic amines.
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PMID:Metabolism of daunorubicin by a barbiturate-sensitive aldehyde reductase from rat liver. 100 38

1. Enzyme systems responsible for formation of cyclopropane ring-cleavage metabolites (M1 and M2) of illudin S in rat liver were characterized. 2. The enzymes were localized in the cytosol fraction and utilized NADPH alone as electron donor; they were not affected by oxygen and had low pH optima. 3. Formation of metabolites M1 and M2 was inhibited completely by dicumarol (10(-4) M), an inhibitor of DT-diaphorase. 4. Menadione (10(-4) M) and quercetin (10(-4) M) both inhibited formation of M1 and M2 by 35% and 15%, respectively, but quinacrine, barbital, pyrazole and p-chloromercuribenzoic acid had no significant effect. 5. Results show that the enzyme systems may differ from DT-diaphorase, aldehyde oxidase, xanthine oxidase, ketone reductase, aldose reductase, aldehyde reductase and alcohol dehydrogenase, known cytosolic enzymes responsible for xenobiotic metabolism.
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PMID:Metabolism by rat liver cytosol of illudin S, a toxic substance of Lampteromyces japonicus. II. Characterization of illudin S-metabolizing enzyme. 137 39

Human aldose reductase and aldehyde reductase are members of the aldo-keto reductase superfamily that share three domains of homology and a nonhomologous COOH-terminal region. The two enzymes catalyze the NADPH-dependent reduction of a wide variety of carbonyl compounds. To probe the function of the domains and investigate the basis for substrate specificity, we interchanged cDNA fragments encoding the NH2-terminal domains of aldose and aldehyde reductase. A chimeric enzyme (CH1, 317 residues) was constructed in which the first 71 residues of aldose reductase were replaced with first 73 residues of aldehyde reductase. Catalytic effectiveness (kcat/Km) of CH1 for the reduction of various substrates remained virtually identical to wild-type aldose reductase, changing a maximal 4-fold. Deletion of the 13-residue COOH-terminal end of aldose reductase, yielded a mutant enzyme (AR delta 303-315) with markedly decreased catalytic effectiveness for uncharged substrates ranging from 80- to more than 600-fold (average 300-fold). The KmNADPH of CH1 and AR delta 303-315 were nearly identical to that of the wild-type enzyme indicating that cofactor binding is unaffected. The truncated AR delta 303-315 displayed a NADPH/D isotope effect in kcat and an increased D(kcat/Km) value for DL-glyceraldehyde, suggesting that hydride transfer has become partially rate-limiting for the overall reaction. We conclude that the COOH-terminal domain of aldose reductase is crucial to the proper orientation of substrates in the active site.
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PMID:Catalytic effectiveness of human aldose reductase. Critical role of C-terminal domain. 140 Apr 12

Mounting evidence indicates that aldose reductase catalyzed reduction of excess glucose to sorbitol initiates the onset of certain diabetic complications. However, the kidney contains a large amount of aldehyde reductase, another NADPH-dependent reductase. The study was designed to assess the importance of these reductases to sugar alcohol (polyol) production in the kidney. To study the ability to reduce aldoses to polyols, both aldose and aldehyde reductases were purified from rat kidneys. Incubation studies with purified enzymes clearly demonstrated the polyol formation by both enzymes. Galactose feeding induced polyol accumulation in both medulla and cortex of the rat kidney. Al 1576, a potent inhibitor of both enzymes, reduced this polyol accumulation in both cortex and medulla, while the selective inhibitors Ponalrestat or FK 366 resulted in greater inhibition in medulla than cortex. These results suggest that kidney polyols may be generated by both aldose and aldehyde reductases and that aldehyde reductase contributes to polyol production in the kidney cortex, the predominant site of diabetes-linked kidney lesions.
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PMID:Rat kidney aldose reductase and aldehyde reductase and polyol production in rat kidney. 144 70

Although the enhanced activity of the polyol pathway has been detected in diabetic glomeruli, the intraglomerular localization of this pathway has not yet been well defined. In this study, we attempted to identify aldose reductase, a key enzyme of the polyol pathway, in cultured rat mesangial cells and to characterize the properties of this enzyme using enzymological and immunological methods. When the aldose reductase (DL-glyceraldehyde-reducing) activity was analyzed in mesangial cell extract, the Lineweaver-Burk plot showed concave downward curvature, and the Michaelis constant was 0.83 mM DL-glyceraldehyde, and this activity was noncompetitively inhibited by an aldose reductase inhibitor, ICI-128,436. The enzyme activity was enhanced by the addition of sulfate ion and partially suppressed by barbital. The enzyme cross-reacted with the antisera against rat lens and testis aldose reductases on Ouchterlony plate, and migrated to the region of molecular weight of about 36,500 Da on Western blotting. The presence of aldose reductase mRNA was also confirmed by Northern analysis using cDNA for rat aldose reductase, 10Q. From these results, it was concluded that the aldose reductase may exist in rat glomerular mesangial cells and may play a role in the development of diabetic glomerulopathy, though the coexistence of aldehyde reductase(s) may not be fully ruled out.
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PMID:Identification and characterization of aldose reductase in cultured rat mesangial cells. 149 67

The distribution of microbial aldo-keto reductases was examined and their immunochemical characterization was performed. p-Nitrobenzaldehyde, pyridine-3-aldehyde and ethyl 4-chloro-3-oxobutanoate reductase activities were found to be widely distributed in a variety of microorganisms. In immunodiffusion studies, most yeasts belonging to the genera Sporobolomyces, Sporidiobolus and Rhodotorula formed precipitin bands with anti-Sporobolomyces salmonicolor aldehyde reductase serum. Furthermore, the results of immunotitration experiments suggested that Sporobolomyces salmonicolor AKU 4429 contains other enzyme(s) which can reduce p-nitrobenzaldehyde, pyridine-3-aldehyde and/or ethyl 4-chloro-3-oxobutanoate, and which are inactivated by anti-Sporobolomyces salmonicolor aldehyde reductase serum.
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PMID:Distribution and immunological characterization of microbial aldehyde reductases. 151 May 61

The substrate specificities of human aldose reductase and aldehyde reductase toward trioses, triose phosphates, and related three-carbon aldehydes and ketones were evaluated. Both enzymes are able to catalyze the NADPH-dependent reduction of all of the substrates used. Aldose reductase shows more discrimination among substrates than does aldehyde reductase and is generally the more efficient catalyst. The best substrate for aldose reductase is methylglyoxal (kcat = 142 min-1, kcat/Km = 1.8 x 10(7) M-1 min-1), a toxic 2-oxo-aldehyde that is produced nonenzymatically from triose phosphates and enzymatically from acetone/acetol metabolism. D- and L-glyceraldehyde and D- and L-lactaldehyde are also good substrates for aldose reductase. The aldose reductase-catalyzed reduction of methylglyoxal produces 95% acetol, 5% D-lactaldehyde. Further reduction of acetol produces only L-1,2-propanediol. Acetol and propanediol are two products that accumulate in uncontrolled diabetes. Both acetol and methylglyoxal were compared with glucose for their abilities to produce covalent modification of albumin. All three of these carbonyl compounds reacted with albumin to produce modified proteins with new absorption and emission bands that are spectrally similar. Both methylglyoxal and acetol are much more reactive than glucose. A new integrative model of diabetic complications is proposed that combines the aldose reductase/polyol pathway theory and the nonenzymatic glycation theory except that emphasis is placed both on methylglyoxal/acetol metabolism and on glucose metabolism.
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PMID:Reduction of trioses by NADPH-dependent aldo-keto reductases. Aldose reductase, methylglyoxal, and diabetic complications. 153 26


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