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: KEGG:D02011 (FAD)
5,530 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

Procedures for the purification of an aldehyde dehydrogenase from extracts of the obligate methylotroph, Methylomonas methylovora are described. The purified enzyme is homogeneous as judged from polyacrylamide gel electrophoresis. In the presence of an artificial electron acceptor (phenazine methosulfate), the purified enzyme catalyzes the oxidation of straight chain aldehydes (C1--C10 tested), aromatic aldehydes (benzaldehyde, salicylaldehyde), glyoxylate, and glyceraldehyde. Biological electron acceptors such as NAD+, NADP+, FAD, FMN, pyridoxal phosphate, and cytochrome c cannot act as electron carriers. The activity of the enzyme is inhibited by sulfhydryl agents [p-chloromercuribenzoate, N-ethylmaleimide and 5,5-dithiobis (2-nitrobenzoic acid)], cuprous chloride, and ferrour nitrate. The molecular weight of the enzyme as estimated by gel filtration is approximately 45000 and the subunit size determined by sodium dodecyl sulfate-gel electrophoresis is approximately 23000. The purified enzyme is light brown and has an absorption peak at 410 nm. Reduction of enzyme with sodium dithionite or aldehyde substrate resulted in the appearance of peaks at 523 nm and 552nm. These results suggest that the enzyme is a hemoprotein. There was no evidence that flavins were present as prosthetic group. The amino acid composition of the enzyme is also presented.
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PMID:Microbial oxidation of methane and methanol: purification and properties of a heme-containing aldehyde dehydrogenase from Methylomonas methylovora. 4 58

Cell-free extracts of methanol-grown Amycolatopsis methanolica contain dye-linked dehydrogenase activities for formate and methyl formate. Fractionation of the extracts revealed that the (unstable) activity for formate resides in membrane particles, while that for methyl formate belongs to a soluble enzyme that was purified and characterized. The enzyme, indicated as formate-ester dehydrogenase, appeared to be a molybdoprotein (4 Fe, 3 or 4 S, 1 Mo and 1 FAD were found for each enzyme molecule), with a molecular mass of 186 kDa and consisting of two subunits of equal size. Product identification suggests that the formate moiety in the ester becomes hydroxylated to a carbonate group after which the unstable alkyl carbonate decomposes into CO2 and the alcohol moiety. Based on structural and catalytic characteristics, the enzyme appears to be very similar to an enzyme isolated from Comamonas testosteroni [Poels, P. A., Groen, B. W. & Duine, J. A. (1987) Eur. J. Biochem. 166, 575-579] which was at that time considered to be an aldehyde dehydrogenase. Formate-ester dehydrogenase activity appeared to be present in several other bacteria. Possible roles for the A. methanolica enzyme in C1 dissimilation (oxidation of methyl formate to methanol and CO2 or a factor-formate adduct to factor plus CO2) or in general aldehyde oxidation, are discussed.
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PMID:Dye-linked dehydrogenase activities for formate and formate esters in Amycolatopsis methanolica. Characterization of a molybdoprotein enzyme active with formate esters and aldehydes. 159 91

Aldehyde dehydrogenase from Pseudomonas testosteroni was purified to homogeneity. The enzyme has a pH optimum of 8.2, uses a wide range of aldehydes as substrates and cationic dyes (Wurster's blue, phenazine methosulphate and thionine), but not anionic dyes (ferricyanide and 2.6-dichloroindophenol), NAD(P)+ or O2, as electron acceptors. Haem c and pyrroloquinoline quinone appeared to be absent but the common cofactors of molybdenum hydroxylases were present. Xanthine was not a substrate and allopurinol was not an inhibitor. Alcohols were inhibitors only when turnover of the enzyme occurred in aldehyde conversion. The enzyme has a relative molecular mass of 186,000, consists of two subunits of equal size (Mr 92,000), and 1 enzyme molecule contains 1 FAD, 1 molybdopterin cofactor, 4 Fe and 4 S. It is a novel type of NAD(P)+-independent aldehyde dehydrogenase since its catalytic and physicochemical properties are quite different from those reported for already known aldehyde-converting enzymes like haemoprotein aldehyde dehydrogenase (EC 1.2.99.3), quino-protein alcohol dehydrogenases (EC 1.1.99.8) and molybdenum hydroxylases.
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PMID:NAD(P)+-independent aldehyde dehydrogenase from Pseudomonas testosteroni. A novel type of molybdenum-containing hydroxylase. 360 27

Methanol-grown Amycolatopsis methanolica NCIB 11946 contains a molybdoprotein dehydrogenase, active with aldehydes and formate esters as substrates and with Wurster's blue as electron acceptor, the so-called formate ester dehydrogenase (FEDH) (van Ophem et al., 1992, Eur. J. Biochem. 206, 519-525). It appears now that another molybdoprotein dehydrogenase is present in this organism. This enzyme, indicated here as dye-linked aldehyde dehydrogenase (DL-AlDH), has the same set of cofactors and converts the same type of substrates but with different specificity, and uses 2,6-dichlorophenol-indophenol as sole artificial electron acceptor for those conversions. The enzymes also differ in their quaternary structure, FEDH having an alpha, beta, gamma and DL-AlDH having an alpha, beta, gamma 2 composition. Furthermore, differences exist with respect to the sizes and the N-terminal amino acid sequences of their subunits, indicating that the enzymes derive from different genes. However, neither their substrate specificity nor their induction pattern give a clear indication for distinct physiological roles. Just like other bacterial molybdoprotein dehydrogenases, DL-AlDH consists of three different subunits (87, 35, and 17 kDa) and contains FAD, molybdopterin-cytosine-dinucleotide cofactor, Fe, and acid-labile sulfide in a molar ratio of 1:1:4:4. Although eukaryotic xanthine oxidase and dehydrogenase differ from these prokaryotic dehydrogenases in size and number of their subunits, certain stretches of amino acid sequences show similarity and the magnetic coupling between the Mo and the [2Fe-2S]-1 cluster in DL-AlDH and bovine milk xanthine oxidase is of the same magnitude. In view of this similarity, the topology of the cofactors in the active site of this type of molybdoproteins might be conserved among enzymes from prokaryotic as well as eukaryotic organisms.
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PMID:A second molybdoprotein aldehyde dehydrogenase from Amycolatopsis methanolica NCIB 11946. 855 33

The aldehyde dehydrogenase activity of the sulfate-reducing bacterium Desulfovibrio simplex strain DSM 4141 was characterized in cell-free extracts. Oxygen-sensitive, constitutive aldehyde dehydrogenase activity was found in cells grown on l(+)-lactate, hydrogen, or vanillin with sulfate as the electron acceptor. A 1.83- to 2.6-fold higher specific activity was obtained in cells grown in media supplemented with 1 microM WO42-. The aldehyde dehydrogenase in cell-free extracts catalyzed the oxidation of aliphatic (Km < 20 microM) and aromatic aldehydes (Km < 0.32 mM) using methyl viologen as the electron acceptor. Flavins (FMN and FAD) were also active and are proposed to be the natural cofactors, while no activity was obtained with NAD+ or NADP+. 185WO42- was incorporated in vivo into D. simplex; it was found exclusively in the soluble fraction (>/= 98%). Anionic-exchange chromatography demonstrated coelution of 185W with two distinct peaks, the first one containing hydrogenase and formate dehydrogenase activities, and the second one aldehyde dehydrogenase activity.
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PMID:Evidence for a tungsten-stimulated aldehyde dehydrogenase activity of Desulfovibrio simplex that oxidizes aliphatic and aromatic aldehydes with flavins as coenzymes. 938 39

Biological oxidation of cyclic ketones normally results in formation of the corresponding dicarboxylic acids, which are further metabolized in the cell. Rhodococcus ruber strain SC1 was isolated from an industrial wastewater bioreactor that was able to utilize cyclododecanone as the sole carbon source. A reverse genetic approach was used to isolate a 10-kb gene cluster containing all genes required for oxidative conversion of cyclododecanone to 1,12-dodecanedioic acid (DDDA). The genes required for cyclododecanone oxidation were only marginally similar to the analogous genes for cyclohexanone oxidation. The biochemical function of the enzymes encoded on the 10-kb gene cluster, the flavin monooxygenase, the lactone hydrolase, the alcohol dehydrogenase, and the aldehyde dehydrogenase, was determined in Escherichia coli based on the ability to convert cyclododecanone. Recombinant E. coli strains grown in the presence of cyclododecanone accumulated lauryl lactone, 12-hydroxylauric acid, and/or DDDA depending on the genes cloned. The cyclododecanone monooxygenase is a type 1 Baeyer-Villiger flavin monooxygenase (FAD as cofactor) and exhibited substrate specificity towards long-chain cyclic ketones (C11 to C15), which is different from the specificity of cyclohexanone monooxygenase favoring short-chain cyclic compounds (C5 to C7).
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PMID:Cloning and characterization of a gene cluster for cyclododecanone oxidation in Rhodococcus ruber SC1. 1159 93

This paper summarizes studies on microbial degradation of polyethers. Polyethers are aerobically metabolized through common mechanisms (oxidation of terminal alcohol groups followed by terminal ether cleavage), well-characterized examples being found with polyethylene glycol (PEG). First the polymer is oxidized to carboxylated PEG by alcohol and aldehyde dehydrogenases and then the terminal ether bond is cleaved to yield the depolymerized PEG by one glycol unit. Most probably PEG is anaerobically metabolized through one step which is catalyzed by PEG acetaldehyde lyase, analogous to diol dehydratase. Whether aerobically or anaerobically, the free OH group is necessary for metabolization of PEG. PEG with a molecular weight of up to 20,000 was metabolized either in the periplasmic space (Pseudomonas stutzeri and sphingomonads) or in the cytoplasm (anaerobic bacteria), which suggests the transport of large PEG through the outer and inner membranes of Gram-negative bacterial cells. Membrane-bound PEG dehydrogenase (PEG-DH) with high activity towards PEG 6,000 and 20,000 was purified from PEG-utilizing sphingomonads. Sequencing of PEG-DH revealed that the enzyme belongs to the group of GMC flavoproteins, FAD being the cofactor for the enzyme. On the other hand, alcohol dehydrogenases purified from other bacteria that cannot grow on PEG oxidized PEG. Cytoplasmic NAD-dependent alcohol dehydrogenases with high specificity towards ether-alcohol compound, either crude or purified, showed appreciable activity towards PEG 400 or 600. Liver alcohol dehydrogenase (equine) also oxidized PEG homologs, which might cause fatal toxic syndrome in vivo by carboxylating PEG together with aldehyde dehydrogenase when PEG was absorbed. An ether bond-cleaving enzyme was detected in PEG-utilizing bacteria and purified as diglycolic acid (DGA) dehydrogenase from a PEG-utilizing consortium. The enzyme oxidized glycolic acid, glyoxylic acid, as well as PEG-carboxylic acid and DGA. Similarly, dehydrogenation on polypropylene glycol (PPG) and polytetramethylene glycol (PTMG) was suggested with cell-free extracts of PPG and PTMG-utilizing bacteria, respectively. PPG commercially available is atactic and includes many structural (primary and secondary alcohol groups) and optical (derived from pendant methyl groups on the carbon backbone) isomers. Whether PPG dehydrogenase (PPG-DH) has wide stereo- and enantioselective substrate specificity towards PPG isomers or not must await further purification. Preliminary research on PPG-DH revealed that the enzyme was inducibly formed by PPG in the periplasmic, membrane and cytoplasm fractions of a PPG-utilizing bacterium Stenotrophomonas maltophilia. This finding indicated the intracellular metabolism of PPG is the same as that of PEG. Besides metabolization of polyethers, a biological Fenton mechanism was proposed for degradation of PEG, which was caused by extracellular oxidants produced by a brown-rot fungus in the presence of a reductant and Fe3+, although the metabolism of fragmented PEG has not yet been well elucidated.
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PMID:Microbial degradation of polyethers. 1183 73

As many as one-third of mutations in a gene result in the corresponding enzyme having an increased Michaelis constant, or K(m), (decreased binding affinity) for a coenzyme, resulting in a lower rate of reaction. About 50 human genetic dis-eases due to defective enzymes can be remedied or ameliorated by the administration of high doses of the vitamin component of the corresponding coenzyme, which at least partially restores enzymatic activity. Several single-nucleotide polymorphisms, in which the variant amino acid reduces coenzyme binding and thus enzymatic activity, are likely to be remediable by raising cellular concentrations of the cofactor through high-dose vitamin therapy. Some examples include the alanine-to-valine substitution at codon 222 (Ala222-->Val) [DNA: C-to-T substitution at nucleo-tide 677 (677C-->T)] in methylenetetrahydrofolate reductase (NADPH) and the cofactor FAD (in relation to cardiovascular disease, migraines, and rages), the Pro187-->Ser (DNA: 609C-->T) mutation in NAD(P):quinone oxidoreductase 1 [NAD(P)H dehy-drogenase (quinone)] and FAD (in relation to cancer), the Ala44-->Gly (DNA: 131C-->G) mutation in glucose-6-phosphate 1-dehydrogenase and NADP (in relation to favism and hemolytic anemia), and the Glu487-->Lys mutation (present in one-half of Asians) in aldehyde dehydrogenase (NAD + ) and NAD (in relation to alcohol intolerance, Alzheimer disease, and cancer).
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PMID:High-dose vitamin therapy stimulates variant enzymes with decreased coenzyme binding affinity (increased K(m)): relevance to genetic disease and polymorphisms. 1191 49

The amino acid beta-alanine is an intermediate in pantothenic acid (vitamin B(5)) and coenzyme A (CoA) biosynthesis. In contrast to bacteria, yeast derive the beta-alanine required for pantothenic acid production via polyamine metabolism, mediated by the four SPE genes and by the FAD-dependent amine oxidase encoded by FMS1. Because amine oxidases generally produce aldehyde derivatives of amine compounds, we propose that an additional aldehyde-dehydrogenase-mediated step is required to make beta-alanine from the precursor aldehyde, 3-aminopropanal. This study presents evidence that the closely related aldehyde dehydrogenase genes ALD2 and ALD3 are required for pantothenic acid biosynthesis via conversion of 3-aminopropanal to beta-alanine in vivo. While deletion of the nuclear gene encoding the unrelated mitochondrial Ald5p resulted in an enhanced requirement for pantothenic acid pathway metabolites, we found no evidence to indicate that the Ald5p functions directly in the conversion of 3-aminopropanal to beta-alanine. Thus, in Saccharomyces cerevisiae, ALD2 and ALD3 are specialized for beta-alanine biosynthesis and are consequently involved in the cellular biosynthesis of coenzyme A.
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PMID:Specialization of function among aldehyde dehydrogenases: the ALD2 and ALD3 genes are required for beta-alanine biosynthesis in Saccharomyces cerevisiae. 1258 97

Choline oxidase catalyzes the four-electron oxidation of choline to glycine betaine via two sequential FAD-dependent reactions in which betaine aldehyde is formed as an intermediate. The chemical mechanism for the oxidation of choline catalyzed by choline oxidase was recently elucidated by using kinetic isotope effects [Fan, F., and Gadda, G. (2005) J. Am. Chem. Soc. 127, 2067-2074]. In this study, the oxidation of betaine aldehyde has been investigated by using spectroscopic and kinetic analyses with betaine aldehyde and its isosteric analogue 3,3-dimethylbutyraldehyde. The pH dependence of the kcat/Km and kcat values with betaine aldehyde showed that a catalytic base with a pKa of approximately 6.7 is required for betaine aldehyde oxidation. Complete reduction of the enzyme-bound flavin was observed in a stopped-flow spectrophotometer upon anaerobic mixing with betaine aldehyde or choline at pH 8, with similar k(red) values > or = 48 s(-1). In contrast, only 10-26% of the enzyme-bound flavin was reduced by 3,3-dimethylbutyraldehyde between pH 6 and 10. Furthermore, this compound acted as a competitive inhibitor versus choline. NMR spectroscopic analyses indicated that betaine aldehyde exists predominantly (99%) as a diol form in aqueous solution. In contrast, the thermodynamic equilibrium for 3,3-dimethylbutyraldehyde favors the aldehyde (> or = 65%) over the hydrated form in the pH range from 6 to 10. The keto species of 3,3-dimethylbutyraldehyde is reactive toward enzymic nucleophiles, as suggested by the kinetic data with NAD+-dependent yeast aldehyde dehydrogenase. The data presented suggest that choline oxidase utilizes the hydrated species of the aldehyde as substrate in a mechanism for aldehyde oxidation in which hydride transfer is triggered by an active site base.
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PMID:Mechanistic studies of choline oxidase with betaine aldehyde and its isosteric analogue 3,3-dimethylbutyraldehyde. 1646 45


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