Studies of yeast alcohol dehydrogenase with 3-aminopyridine mononucleotide

Summary 3-Aminopyridine mononucleotide, a nicotinamide mononucleotide analog, was prepared by enzymatic cleavage of 3-aminopyridine adenine dinucleotide by a snake venom phosphodiesterase and isolated by means of ion exchange chromatography. The spectrophotometric and fluorometric properties of this analog were studied. Several anions were shown to quench the fluorescence intensity of this analog. pH was shown to have a pronounced effect on the fluorescence intensity. 3-Aminopyridine mononucleotide was shown to be a coenzyme-competitive inhibitor of yeast alcohol dehydrogenase. The 3-aminopyridine mononucleotide was diazotized with the use of nitrous acid. A time dependent irreversible inactivation of yeast alcohol dehydrogenase resulted from incubation with the diazotized 3-aminopyridine mononucleotide at pH 7.0. Incubation of the enzyme with NAD prior to the addition of the diazotized 3-aminopyridine mononucleotide protected the enzyme against inactivation.Recently, 3-aminopyridine adenine dinucleotide (AAD) and 3-aminopyridine adenine dinucleotide phosphate (AADP), NAD and NADP analogs respectively, were synthesized by either chemical or enzymatic processes. The chemical, spectrophotometric properties of these dinucleotides have also been reported. It was demonstrated that these nucleotides serve as coenzyme-competitive inhibitors of dehydrogenases but did not function as coenzymes for oxidation-reduction reactions catalyzed by these enzymes. The pyridine amino group of AAD was diazotized and the diazotized derivative was shown to inactive yeast alcohol dehydrogenase irreversibly. Isolation of modified cysteine residue from the modified yeast alcohol dehydrogenase resulting from inactivation by diazotized AAD has been reported. Thus, diazotized AAD proved to be a site specific label for the coenzyme binding site of yeast alcohol dehydrogenase. It was of interest to prepared and determine the properties of a NMN analog, 3-aminopyridine mononucleotide (APMN). The preparation of APMN was accomplished by enzymatic cleavage of AAD with snake venom phosphodiesterase according to a method previously reported. This report deals with the preparation, properties and studies of APMN with yeast alcohol dehydrogenase.This work was supported in part by Research Grant GR-IX from Old Dominion University Research Foundation.     

Properties of 3-aldoxime pyridine adenine dinucleotide, an NAD analogue

The NAD⁺ analogue, 3-aldoxime pyridine adenine dinucleotide, is prepared by transglycosidation. Contrary to the published data, this analogue shows no activity as coenzyme with alcohol dehydrogenase from horse liver or from yeast. This is demonstrated by three methods: no increase of absorption at 331 nm by the enzymic oxidation of ethanol; no increase at 290 nm with cinnamic alcohol; and no exchange reaction. The inhibition by this analogue of the oxidation of ethanol by NAD⁺ is competitive at pH 7.6 and 9.5 with yeast alcohol dehydrogenase; with liver alcohol dehydrogenase, it is of the mixed type at pH 7.6 and non-competitive at pH 9.5. The lack of activity of the analogue and inhibition of the competitive or mixed type may be explained by the fact that the binary complex does not bind the substrate or that in the ternary complex the hydride shift does not occur. The non-competitive inhibition at pH 9.5 with the horse liver alcohol dehydrogenase may be explained by the existence of binding sites specific for this analogue.     

Synthesis and properties of (4-13C)NAD+. Observation of its binding to yeast alcohol dehydrogenase by 13C-NMR spectroscopy

Starting from (13C)formic acid, acetone and cyanoacetamide samples of (4-13C)nicotinic acid and (4-13C)-nicotinamide were synthesised in an overall and additive yield of 11%. 1H-NMR and mass spectroscopy showed 90% enrichment of 13C in the expected position. NADase-catalysed exchange between thionicotinamide-adenine dinucleotide and (4-13C)nicotinamide furnished (4-13C)NAD+ which was purified, characterized and quantified by 1H-NMR and 13C-NMR spectroscopy and by enzymic assay. The 13C-NMR signal of (4-13C)beta-NAD+ (146.09 ppm) was broadened and shifted (147.83 ppm) upon binding to yeast alcohol dehydrogenase.     

Preparation and characterization of the NAD vinylogue, 3-pyridylacryloamide adenine dinucleotide

The vinylogue of NAD, 3-pyridylacryloamide adenine dinucleotide, was prepared from NAD and 3-pyridylacryloamide through the snake venom NADase-catalyzed transglycosidation reaction. The analog, purified by ion-exchange chromatography, was obtained in a 55% yield. The cyanide adduct and reduced form of the analog exhibited absorbance maxima at 358 nm and 378 nm, respectively, with extinction coefficients in each case being 2.3-times higher than those reported for the corresponding NAD derivatives. 3-Pyridylacryloamide adenine dinucleotide served as a coenzyme with bovine liver glutamic dehydrogenase and to a lesser extent with malate and lactate dehydrogenases. The analog was not reduced in reactions catalyzed by yeast and horse liver alcohol dehydrogenases, sheep liver sorbitol dehydrogenase, and rabbit muscle glycerophosphate dehydrogenase. Substitution of the pyridylacryloamide analogs for NAD and NADH in the assay of substrates for glutamic dehydrogenase was demonstrated.     

A novel diazonium-sulfhydryl reaction in the inactivation of yeast alcohol dehydrogenase by diazotized 3-aminopyridine adenine dinucleotide.

Diazotized 3-aminopyridine adenine dinucleotide has been found to modify four sulfhydryl groups per molecule of enzyme during the complete inactivation of yeast alcohol dehydrogenase. The reaction of sulfhydryl groups was indicated by titration studies with 5,5-dithiobis(2-nitrobenzoic acid) as well as isolation and quantitation of the cysteinyl derivative released by acid hydrolysis of the modified enzyme. The cysteinyl derivative was identified as S-(3-pyridyl)cysteine. Authentic S-(3-pyridyl)cystein was synthesized and structurally characterized for these studies. Diazonium-sulfhydryl reactions were demonstrated for a number of diazonium derivatives with cysteine, homocysteine, glutathione, and mercaptoethanol at 0-4 degrees and neutral pH. Second order rate constants were determined in reactions of these sulfhydryl compounds with diazotized 1-methyl-3-aminopyridinium chloride, diazotized 3-aminopyridine adenine dinucleotide, and diazotized 3-aminopyridine adenine dinucleotide phosphate.     

Carbanicotinamide adenine dinucleotide: synthesis and enzymological properties of a carbocyclic analogue of oxidized nicotinamide adenine dinucleotide

The dinucleotide carbanicotinamide adenine dinucleotide (carba-NAD), in which a 2,3-dihydroxycyclopentane ring replaces the beta-D-ribonucleotide ring of the nicotinamide ribonucleoside moiety of NAD, has been synthesized and characterized enzymologically. The synthesis begins with the known 1-aminoribose analogue (+/-)-4 beta-amino-2 alpha,3 alpha-dihydroxy-1 beta-cyclopentanemethanol. The pyridinium ring is first introduced and the resultant nucleoside analogue specifically 5'-phosphorylated. Coupling the racemic carbanicotinamide 5'-mononucleotide with adenosine 5'-monophosphate produces two diastereomeric carba-NAD analogues which are chromatographically separable. Only one diastereomer is a substrate for alcohol dehydrogenase and on this basis is assigned a configuration analogous to D-ribose. The reduced dinucleotide carba-NADH was characterized by fluorescence spectroscopy and found to adopt a "stacked" conformation similar to that of NADH. The analogue is reduced by both yeast and horse liver alcohol dehydrogenase with Km and Vmax values for the analogue close to those observed for NAD. Carba-NAD is resistant to cleavage by NAD glycohydrolase, and the analogue has been demonstrated to noncovalently inhibit the soluble NAD glycohydrolase from Bungarus fasciatus venom at low concentrations (less than or equal to 100 microM).     

Preparation, purification and analyses of thirteen alkali-stable dinucleotides from ribonucleic acid

Of the 16 alkali-stable dinucleotides known to be obtained by hydrolysis of commercial yeast RNA with alkali, 13 were prepared in quantities of the order of 10mg or more. The samples, with only one exception, contain at least 90% of dinucleotide, and spectroscopic constants and nucleotide-sequence determinations, although not conclusive, indicate a high degree of purity of these products. The small dinucleotide fraction in 150g of RNA hydrolysed with alkali (1-2% of the total nucleotides) was separated from the mononucleotides by stepwise ion-exchange chromatography on DEAE-cellulose columns and resolved into seven fractions containing from one to four different dinucleotides by electrophoresis on paper at pH3.0. These fractions were resolved into their constituent dinucleotides by chromatography in ammonium sulphate. Contamination of the products by impurities from the paper was minimized by washing it before using it for chromatography or electrophoresis and, by using a thick grade of paper (Whatman no. 17), it was possible to handle and purify relatively large quantities of nucleotides.     

The recycling of NAD+ (free and immobilized) within semipermeable aqueous microcapsules containing a multi-enzyme system.

Semipermeable aqueous collodion microcapsules were prepared containing both yeast alcohol dehydrogenase (EC 1.1.1.1) and malic dehydrogenase (EC 1.1.1.37). These microcapsules exhibited both enzymic activities in good amount in the ratio 3:1 with respect to malic dehydrogenase:alcohol dehydrogenase.Both NAD⁺ and NADH were successfully cycled within the microcapsules by employing the included enzyme activities acting sequentially. A soluble, immobilized NAD⁺ derivative was also recycled within the semipermeable microcapsules.     

Influence of coenzyme structure on the transient chemical intermediate formed during horse-liver alcohol-dehydrogenase-catalyzed reduction of aromatic aldehydes

The influence of coenzyme structure on the transient chemical intermediate formed in the reaction between the horse-liver alcohol dehydrogenase-NADH complex and an aromatic aldehyde such as 4-trans-(N,N-dimethylamino)cinnamaldehyde or 4-(N,N-dimethylamino)benzaldehyde was investigated by substituting various adenylic dinucleotides for NADH. Two classes of dinucleotide were studied. (a) Dinucleotides which, in the presence of horse-liver alcohol dehydrogenase and either 4-(N,N-dimethylamino)benzaldehyde or 4-trans-(N,N-dimethylamino)cinnamaldehyde, lead to a chromophore structurally analogous to the transient chemical intermediate formed with NADH under the same experimental conditions. This includes dinucleotides with a neutral 1,4-dihydropyridine ring, analogues of NADH and adducts of NAD+ (or analogues) with enolizable carbonyl compounds. (b) Dinucleotides which, under the same experimental conditions, do not form any new chromophores when mixed with horse-liver alcohol dehydrogenase and either 4-trans-(N,N-dimethylamino)cinnamaldehyde or 4-trans-(N,N-dimethylamino)benzaldehyde. This includes oxidized coenzyme analogues, NADPH and NADP+ adducts. Our data suggest that a neutral 1,4-dihydropyridine ring is crucial for the formation of the transient chemical intermediate. When the NAD+-sulphite complex, which has a 1,4-dihydronicotinamide structure and a positive charge at position 4 neutralized by sulphite ions, was substituted for NADH, the transient chemical intermediate chromophore was observed. The implications of this phenomenon are examined by assuming the existence of intermediate-activated forms of substrates and coenzymes during the horse-liver alcohol dehydrogenase catalytic reduction of aldehydes.     

Reduction of acetaldehyde to ethanol by some micro-organisms and its stereospecificity.

The stereochemical course of the reduction of acetaldehyde to ethanol was investigated by evaluating, with the enzymic system yeast alcohol dehydrogenase/diaphorase and g.c.-m.s., the configuration of [1-2H]ethanol obtained from [1-2H]acetaldehyde with different micro-organisms. Although only S-[1-2H]ethanol was formed, all the micro-organisms showed evidence of the existence of alcohol dehydrogenases with opposite stereospecificity.     

New coenzymically-active soluble and insoluble macromolecular NAD+ derivatives.

Reaction in dimethyl sulfoxide of nicotinamide 8-bromoadenine dinucleotide with the disodium salt of 3-mercaptopropionic acid afforded nicotinamide-8-(2-carboxyethylthio)adenine dinucleotide, a new NAD+ analogue functionalized at the adenine C-8 position by an omega-carboxylic side chain. Carbodimide coupling of the latter derivative to high-molecular-weight water-soluble (polyethyleneimine, polylysine) and insoluble (aminohexy)-Sepharose) polymers gave the corresponding macromolecular NAD+ analogues. These derivatives have been shown to be enzymically reducible. The polyethyleneimine analogue showed a substantial degree of efficiency relative to free NAD+ with yeast alcohol dehydrogenase (47%) but a considerably lower one with rabbit muscle lactate dehydrogenase (3%); the polylysine analogue showed a low degree of efficiency with both enzymes (5-6%).     

The conformation of adenosine diphosphoribose and 8-bromoadenosine diphosphoribose when bound to liver alcohol dehydrogenase.

8-Bromo-adenosine diphosphoribose (br8 ADP-Rib) and nicotinamide 8-bromoadenine dinucleotide (Nbr8AD+) which are analogues of the coenzyme NAD+, were prepared and their liver alcohol dehydrogenase complexes studied by crystallographic methods. Nbr8AD+ is active in alcohol dehydrogenase complexes studied by crystallographic methods. Nbr8AD+ is active in hydrogen transport and br8ADP-Rib is a coenzyme competitive inhibitor for the enzymes liver alcohol dehydrogenase and yeast alcohol dehydrogenase. X-ray data were obtained for the complex between liver alcohol dehydrogenase and br8ADP-Rib to 0.45 nm resolution and for the liver alcohol dehydrogenase-adenosine diphosphoribose complex to 0.29-nm resolution. The conformations of these analogues were determined from the X-ray data. It was found that ADP-Rib had a conformation very similar to the corresponding part of NAD+, when NAD+ is bound to lactate and malate dehydrogenase. br8ADP-Rib had the same anti conformation of the adenine ring with respect to the ribose as ADP-Rib and NAD+, in contrast to the syn conformation found in 8-bromo-adenosine. The overcrowding at the 8-position is relieved in br8ADP-Rib by having the ribose in the 2' endo condormation instead of the usual 3' endo as in ADP-Rib and NAD+.     

A new ternary complex between horse liver alcohol dehydrogenase, NAD+, and acetone

Acetone was found to form a dead-end ternary complex with horse liver alcohol dehydrogenase and oxidized nicotinamide adenine dinucleotide (NAD⁺) when the reactants were incubated for a long time at relatively high concentrations. The complex formation was demonstrated by measuring the increase in absorbance at 320 nm, the quenching of protein fluorescence, and the loss of enzyme activity. Since acetone is a substrate of liver alcohol dehydrogenase, and the presence of acetaldehyde or pyrazole prevents acetone from forming the dead-end complex with liver alcohol dehydrogenase and NAD⁺, the acetone molecule in the complex may be bound to the substrate binding site of liver alcohol dehydrogenase. The dissociation of the complex was demonstrated by prolonged dialysis or by addition of reduced nicotinamide adenine dinucleotide (NADH) and iso-butyramide. A modified nicotinamide adenine dinucleotide was obtained as a main product from the dead-end complex after dissociation of the complex or denaturation of the apoenzyme. The modified nicotinamide adenine dinucleotide was found to exhibit an absorption spectrum similar to that of NADH; however, it was not oxidizable by liver alcohol dehydrogenase in the presence of acetaldehyde and exhibited no fluorescence.     

Chemo-enzymatic synthesis of optically pure rivastigmine intermediate using alcohol dehydrogenase from baker's yeast

An efficient and practical synthesis of (S)-rivastigmine intermediate was developed by employing a chemoenzymatic step toward the synthesis of chiral intermediate N-ethyl-N-methyl-carbamic acid-3-(1S-hydroxy-ethyl)-phenyl ester (2) using crude alcohol dehydrogenase from baker's yeast with reduced nucleotide adenosine dinucleotide (NADH) as proton donor has been demonstrated.     

Inhibition by ethanol, acetaldehyde and trifluoroethanol of reactions catalysed by yeast and horse liver alcohol dehydrogenases.

1. Produced inhibition by ethanol of the acetaldehyde-NADH reaction, catalysed by the alcohol dehydrogenases from yeast and horse liver, was studied at 25 degrees C and pH 6-9. 2. The results with yeast alcohol dehydrogenase are generally consistent with the preferred-pathway mechanism proposed previously [Dickenson & Dickinson (1975) Biochem. J. 147, 303-311]. The observed hyperbolic inhibition by ethanol of the maximum rate of acetaldehyde reduction confirms the existence of the alternative pathway involving an enzyme-ethanol complex. 3. The maximum rate of acetaldehyde reduction with horse liver alcohol dehydrogenase is also subject to hyperbolic inhibition by ethanol. 4. The measured inhibition constants for ethanol provide some of the information required in the determination of the dissociation constant for ethanol from the active ternary complex. 5. Product inhibition by acetaldehyde of the ethanol-NAD+ reaction with yeast alcohol dehydrogenase was examined briefly. The results are consistent with the proposed mechanism. However, the nature of the inhibition of the maximum rate cannot be determined within the accessible range of experimental conditions. 6. Inhibition of yeast alcohol dehydrogenase by trifluoroethanol was studied at 25 degrees C and pH 6-10. The inhibition was competitive with respect to ethanol in the ethanol-NAD+ reaction. Estimates were made of the dissociation constant for trifluoroethanol from the enzyme-NAD+-trifluoroethanol complex in the range pH6-10.     

马肝醇脱氢酶基因的克隆及其在大肠杆菌中的表达

利用RT-PCR技术从马肝扩增HLADH-E和HLADH-S基因,通过基因工程方法构建表达质粒pLY115E和pLY115S,在大肠杆菌中表达,并利用Ni柱分离纯化。利用紫外检测辅酶NADH在340nm的吸光值,来考察表达产物转化环己醇的活性。试验结果证明马肝醇脱氢酶HLADH-E和HLADH-S基因均能在大肠杆菌中表达,并且可溶性表达产物都具有氧化环己醇的活性,为马肝醇脱氢酶的进一步研究开发奠定了基础。     

Relationship between fluorescence and conformation of epsilonNAD+ bound to dehydrogenases.

This work reports on the interaction of the fluorescent nicotinamide 1,N6-ethenoadenine dinucleotide (epsilonNAD+) with horse liver alcohol dehydrogenase, octopine dehydrogenase, and glyceraldehyde-3-phosphate dehydrogenase from different sources (yeast, lobster muscle, and rabbit muscle). The coenzyme fluorescence is enhanced by a factor of 10-13 in all systems investigated. It is shown that this enhancement cannot be due to changes in the polarity of the environment upon binding, and that it must be rather ascribed to structural properties of the bound coenzyme. Although dynamic factors could also be important for inducing changes in the quantum yield of epsilonNAD+ fluorescence, the close similarity of the fluorescence enhancement factor in all cases investigated indicates that the conformation of bound coenzyme is rather invariant in the different enzyme systems and overwhelmingly shifted toward an open form. Dissociation constants for epsilonNAD+-dehydrogenases complexes can be determined by monitoring the coenzyme fluorescence enhancement or the protein fluorescence quenching. In the case of yeast glyceraldehyde-3-phosphate dehydrogenase at pH 7.0 and t = 20 degrees the binding plots obtained by the two methods are coincident, and show no cooperativity. The affinity of epsilonNAD+ is generally lower than that of NAD+, although epsilonNAD+ maintains most of the binding characteristics of NAD+. For example, it forms a tight complex with horse liver alcohol dehydrogenase and pyrazole, and with octopine dehydrogenase saturated by L-arginine and pyruvate. One major difference in the binding behavior of NAD+ and epsilonNAD+ seems to be present in the muscle glyceraldehyde-3-phosphate dehydrogenase. In fact, no difference was found for epsilon NAD+ between the affinities of the third and fourth binding sites. The results and implications of this work are compared with those obtained recently by other authors.     

Secondary 15N isotope effects on the reactions catalyzed by alcohol and formate dehydrogenases

Secondary 15N isotope effects at the N-1 position of 3-acetylpyridine adenine dinucleotide have been determined, by using the internal competition technique, for horse liver alcohol dehydrogenase (LADH) with cyclohexanol as a substrate and yeast formate dehydrogenase (FDH) with formate as a substrate. On the basis of less precise previous measurements of these 15N isotope effects, the nicotinamide ring of NAD has been suggested to adopt a boat conformation with carbonium ion character at C-4 during hydride transfer [Cook, P. F., Oppenheimer, N. J. & Cleland, W. W. (1981) Biochemistry 20, 1817]. If this mechanism were valid, as N-1 becomes pyramidal an 15N isotope effect of up to 2-3% would be observed. In the present study the equilibrium 15N isotope effect for the reaction catalyzed by LADH was measured as 1.0042 +/- 0.0007. The kinetic 15N isotope effect for LADH catalysis was 0.9989 +/- 0.0006 for cyclohexanol oxidation and 0.997 +/- 0.002 for cyclohexanone reduction. The kinetic 15N isotope effect for FDH catalysis was 1.004 +/- 0.001. These values suggest that a significant 15N kinetic isotope effect is not associated with hydride transfer for LADH and FDH. Thus, in contrast with the deformation mechanism previously postulated, the pyridine ring of the nucleotide apparently remains planar during these dehydrogenase reactions.