Rat liver alcohol dehydrogenase. I. Purification and characterization

Alcohol dehydrogenase was purified in 14 h from male Fischer-344 rat livers by differential centrifugation, (NH4)2SO4 precipitation, and chromatography over DEAE-Affi-Gel Blue, Affi-Gel Blue, and AMP-agarose. Following HPLC more than 240-fold purification was obtained. Under denaturing conditions, the enzyme migrated as a single protein band (Mr congruent to 40,000) on 10% sodium dodecyl sulfate-polyacrylamide gels. Under nondenaturing conditions, the protein eluted from an HPLC I-125 column as a symmetrical peak with a constant enzyme specific activity. When examined by analytical isoelectric focusing, two protein and two enzyme activity bands comigrated closely together (broad band) between pH 8.8 and 8.9. The pure enzyme showed pH optima for activity between 8.3 and 8.8 in buffers of 0.5 M Tris-HCl, 50 mM 2-(N-cyclohexylamino)ethanesulfonic acid (CHES), and 50 mM 3-(cyclohexylamino)-1-propanesulfonic acid (CAPS), and above pH 9.0 in 50 mM glycyl-glycine. Kinetic studies with the pure enzyme, in 0.5 M Tris-HCl under varying pH conditions, revealed three characteristic ionization constants for activity: 7.4 (pK1); 8.0-8.1 (pK2), and 9.1 (pK3). The latter two probably represent functional groups in the free enzyme; pK1 may represent a functional group in the enzyme-NAD+ complex. Pure enzyme also was used to determine kinetic constants at 37 degrees C in 0.5 M Tris-HCl buffer, pH 7.4 (I = 0.2). The values obtained were Vmax = 2.21 microM/min/mg enzyme, Km for ethanol = 0.156 mM, Km for NAD+ = 0.176 mM, and a dissociation constant for NAD+ = 0.306 mM. These values were used to extrapolate the forward rate of ethanol oxidation by alcohol dehydrogenase in vivo. At pH 7.4 and 10 mM ethanol, the rate was calculated to be 2.4 microM/min/g liver.     

Purification and properties of benzyl alcohol dehydrogenase from a denitrifying Thauera sp.

Toluene and related aromatic compounds are anaerobically degraded by the denitrifying bacterium Thauera sp. strain K172 via oxidation to benzoyl-CoA. The postulated initial step is methylhydroxylation of toluene to benzyl alcohol, which is either a free or enzyme-bound intermediate. Cells grown with toluene or benzyl alcohol contained benzyl alcohol dehydrogenase, which is possibly the second enzyme in the proposed pathway. The enzyme was purified from benzyl-alcohol-grown cells and characterized. It has many properties in common with benzyl alcohol dehydrogenase from Acinetobacter and Pseudomonas species. The enzyme was active as a homotetramer of 160kDa, with subunits of 40kDa. It was NAD⁺-specific, had an alkaline pH optimum, and was inhibited by thiol-blocking agents. No evidence for a bound cofactor was obtained. Various benzyl alcohol analogues served as substrates, whereas non-aromatic alcohols were not oxidized. The N-terminal amino acid sequence indicates that the enzyme belongs to the class of long-chain Zn²⁺-dependent alcohol dehydrogenases, although it appears not to contain a metal ion that can be removed by complexing agents.Dedicated to Prof. Achim Trebst     

Aromatic alcohol dehydrogenase from potato tubers

The purification of NADP specific aromatic alcohol dehydrogenase is reported. The properties of the enzyme suggest that it should be classified as E.C. 1.1.1.2. Kinetic constants for a number of substrates are reported. The relative rates of reaction of a variety of substituted benzaldehydes have been found to correlate with Hammett's sigma values yielding a biphasic relationship. The physiological significance of the enzyme is briefly discussed.     

Purification and characterization of variant alcohol dehydrogenase isozymes from durum wheat

Three alcohol dehydrogenase (ADH) isozymes from embryos of the durum wheat cultivar Bijaga Yellow having the variantAdh-Alb allele were purified using (NH₄)₂SO₄ precipitation, gel filtration, and ion-exchange chromatography. ADH is a dimeric enzyme. The variant isozyme ADH-1-1, which is a homodimer composed of b monomers, was compared with ADH-1-5 (homodimer composed of a monomers), the product ofAdh-B1, and the ADH-1-3 isozyme (ba heterodimer) on a number of parameters includingK _m, substrate specificities, and molecular weights. No appreciable differences among the three isozymes were found, except for the faster electrophoretic mobility of bb dimers (ADH-1-1). The results indicate that the variant isozyme is the result of a mutation altering only the charge of the isozyme.     

Rhodococcus erythropolis 手性醇脱氢酶的克隆表达及其性质

【目的】探讨红串红球菌中一种醇脱氢酶的性质及其对酮酯类及酮类底物的催化能力。【方法】从红串红球菌(Rhodococcus erythropolis ATCC 4277)中获取一段长度为1047 bp的醇脱氢酶(adh)基因,插入载体pET-22b(+)后,在大肠杆菌中进行重组表达。15℃的低温下用自诱导培养基诱导24 h,以苯乙酮为底物测定醇脱氢酶酶活。【结果】测得该诱导条件下重组菌体细胞破碎上清中醇脱氢酶酶活力为2.6 U/mg。经温度、pH耐受性等分析,发现该酶最适pH在6.0-6.5之间,耐受温度可以达到60℃,并且在该温度下保持5 h后,酶活也能保留80%。对于β酮酯类底物的催化反应,以对乙酰乙酸乙酯的催化能力最高。用4-氯乙酰乙酸乙酯(COBE)为底物进行全细胞水相催化反应,经手性液相色谱分析,发现在催化产物以R型4-氯-3羟基丁酸乙酯(CHBE)为主。【结论】该酶在酮酯类的底物转化方面有良好的开发潜力及应用前景。     

蓝杆藻ATCC51142中琥珀酸半醛脱氢酶的原核表达及生化表征

【背景】蓝藻中生成琥珀酸的三羧酸循环途径与其他物种不同。由于α-酮戊二酸脱羧酶和琥珀酸半醛脱氢酶的存在使得蓝藻的三羧酸循环途径变得完整。琥珀酸半醛脱氢酶催化琥珀酸半醛氧化为琥珀酸,在蓝藻中广泛存在。【目的】克隆、表达和纯化蓝杆藻ATCC51142中cce4228基因编码蛋白,并对其进行生化表征。【方法】以蓝杆藻ATCC51142基因组为模板克隆得到cce4228基因,将其插入到原核表达载体pET-28a上,在大肠杆菌BL21(DE3)细胞中进行异源表达,利用Ni-NTA树脂纯化cce4228蛋白。运用紫外分光光度法和生物信息学方法表征重组cce4228蛋白生化特性。【结果】构建了pET-28a-cce4228重组表达质粒,重组cce4228蛋白在大肠杆菌中得到可溶性表达,获得了纯度大于90%的cce4228蛋白。酶动力学测试和生物信息学分析结果显示,cce4228蛋白是一个NADP+-依赖型的琥珀酸半醛脱氢酶。【结论】蓝杆藻ATCC51142中cce4228基因编码一个偏好NADP+辅因子的琥珀酸半醛脱氢酶,cce4228蛋白的生化表征结果为进一步深入研究cce4228蛋白的结构功能关系及催化机制奠定了基础。     

The presence of an NADP-dependent alcohol dehydrogenase activity in Acinetobacter calcoaceticus

Abstract A soluble NADP-dependent alcohol dehydrogenase activity (EC 1.1.1.2) was found in all five strains of Acinetobacter calcoaceticus tested. In A. calcoaceticus NCIB8250, this dehydrogenase was not induced by growth on ethanol, but was present at approximately the same specific activity when this strain was grown on a variety of carbon sources. The specific activity of the NADP-dependent alcohol dehydrogenase is about 10% of the activity of the NAD-dependent alcohol dehydrogenase found in bacteria grown on ethanol. The distinct biochemical properties of the NADP-dependent dehydrogenase showed that this activity was not due to lack of nucleotide specificity of the NAD-dependent dehydrogenase.     

Aliphatic alcohol dehydrogenase from potato tubers

Potato tubers are shown to contain at least 3 alcohol dehydrogenases, one active with NAD and aliphatic alcohols, one active with NADP and terpene alcohols and one active with NADP and aromatic alcohols. The purification of the aliphatic alcohol dehydrogenase is described and its activity with a wide range of substrates is reported. On the basis of substrate specificity, the enzyme is shown to resemble yeast alcohol dehydrogenase rather than liver alcohol dehydrogenase. The enzyme shows high activity with and high affinity for ethanol, activity and affinity decline as the chain length is increased from ethanol to butanol, but a further increase in chain length leads to increased affinity for the alcohol. The physiological significance of the results is briefly discussed.     

Characterization of Two Isozymes of Coniferyl Alcohol Dehydrogenase from Streptomyces sp. NL15-2K

We purified two isozymes of coniferyl alcohol dehydrogenase (CADH I and II) to homogeneity from cell-free extracts of Streptomyces sp. NL15-2K. The apparent molecular masses of CADH I and II were determined to be 143 kDa and 151 kDa respectively by gel filtration, whereas their subunit molecular masses were determined to be 35,782.2 Da and 37,597.7 Da respectively by matrix-assisted laser-desorption ionization time-of-flight mass spectrometry (MALDI-TOF-MS). Thus, it is probable that both isozymes are tetramers. The optimum pH and temperature for coniferyl alcohol dehydrogenase activity were pH 9.5 and 45 °C for CADH I and pH 8.5 and 40 °C for CADH II. CADH I oxidized various aromatic alcohols and allyl alcohol, and was most efficient on cinnamyl alcohol, whereas CADH II exhibited high substrate specificity for coniferyl alcohol, and showed no activity as to the other alcohols, except for cinnamyl alcohol and 3-(4-hydroxy-3-methoxyphenyl)-1-propanol. In the presence of NADH, CADH I and II reduced cinnamaldehyde and coniferyl aldehyde respectively to the corresponding alcohols.     

Purification and characterization of an alcohol dehydrogenase from 1,2-propanediol-grownDesulfovibrio strain HDv

The sulfate-reducing bacterimDesulfovibrio strain HDv (DSM 6830) grew faster on (S)- and on (R, S)-1,2-propanediol (μ_max 0.053 h⁻) than on (R)-propanediol (0.017 h⁻¹) and ethanol (0.027 h⁻¹). From (R, S)-1,2-propanediol-grown cells, an alcohol dehydrogenase was purified. The enzyme was oxygen-labile, NAD-dependent, and decameric; the subunit mol. mass was 48 kDa. The N-terminal amino acid sequence indicated similarity to alcohol dehydrogenases belonging to family III of NAD-dependent alcohol dehydrogenases, the first 21 N-terminal amino acids being identical to those of theDesulfovibrio gigas alcohol dehydrogenase. Best substrates were ethanol and propanol (K _m of 0.48 and 0.33 mM, respectively). (R, S)-1,2-Propanediol was a relatively poor substrate for the enzyme, but activities in cell extracts were high enough to account for the growth rate. The enzyme showed a preference for (S)-1,2-propanediol over (R)-1,2-propanediol. Antibodies raised against the alcohol dehydrogenase ofD. gigas showed cross-reactivity with the alcohol dehydrogenase ofDesulfovibrio strain HDv and with cell extracts of six other ethanol-grown sulfate-reducing bacteria.     

Reactivity of sorbose dehydrogenase from Sinorhizobium sp. 97507 for 1,5-anhydro-d-glucitol

Purified recombinant sorbose dehydrogenase from Sinorhizobium sp. 97507 exhibited high reactivity for 1,5-anhydro-d-glucitol (1,5-AG) and l-sorbose, but little activity for the other sugars or sugar alcohols tested. Kinetic analysis revealed that its catalytic efficiency (k_cat/K_m) for l-sorbose and 1,5-AG is 1.8 × 10² and 1.5 × 10² s^?1·M^?1, respectively.     

Biochemical genetics of alcohol dehydrogenase isozymes in the gray short-tailed opossum (Monodelphis domestica)

Polyacrylamide gel-isoelectric focusing (PAGE-IEF) methods were used to examine the multiplicity, tissue distribution, and biochemical genetics of alcohol dehydrogenase (ADH) isozymes among gray short-tailed opossums (Monodelphis domestica). Seven ADH isozymes were resolved and distinguished on the basis of their isoelectric points, tissue distributions, and substrate and inhibitor specificities. ADH1 and ADH2 exhibited Class I properties and were observed in liver (and intestine) extracts. ADH3, ADH4, and ADH5 showed “high-K _m ” (possibly Class IV) properties, with ADH3 and ADH4 exhibiting high activity in cornea, ear, stomach, and esophagus extracts. ADH6 and ADH7 exhibited Class III properties, including activities as formaldehyde dehydrogenases, with each showing different tissue distribution characteristics; ADH6 was widely distributed, and ADH7 was restricted to prostate extracts. An additional form of formaldehyde dehydrogenase (FDH) was observed, which was inactive with hexenol and ethanol as substrates. Isoelectric point variants were observed for ADH3 (three forms) and for ADH4 (two forms), and the inheritance of ADH3 was studied in 15 families ofM. domestica. The data were consistent with codominant inheritance of two alleles (ADH3*A andADH3*B) at a single autosomal locus (designatedADH3) and with a model involving a dimeric ADH isozyme: ADH3 (γ₂ isozyme, forming three dimers designated γ ₂ ¹ , γ¹ γ², and γ ₂ ² in heterozygous individuals).     

Purification and characterization of mouse alcohol dehydrogenase from two inbred strains that differ in total liver enzyme activity

Alcohol dehydrogenase activity in mouse liver homogenate-supernatants is 1.7 times greater in the C57BL/10 strain than in the BALB/c strain, regardless of whether activity is expressed in units per gram liver, total liver, or milligram DNA. The K _m values for ethanol and NAD⁺, approximately 0.4 and 0.03mm, respectively, of enzyme purified from both strains are similar. Moreover, the K _i for NADH, 1 µm, the pH optimum for ethanol oxidation, 10.5, and the V _max for ethanol oxidation, 160 min^–1, for ADH from the C57BL/10 and BALB/c strains are similar. Therefore, the difference in ADH activity in the two strains cannot be due to differences in the catalytic properties of the enzyme. The electrophoretic and isoelectric focusing patterns and two-dimensional tryptic peptide maps of the purified enzyme from both strains are identical. Thus the amino acid sequences of enzyme from C57BL/10 and BALB/c mice must also be identical or very similar. The difference in ADH activity in the two strains is most likely the result of genetic differences in the content of ADH protein in liver.Supported by NIAAA Grant AA 04307.     

Purification and characterization of a chemotolerant alcohol dehydrogenase applicable to coupled redox reactions

The purification and characterization of an organic solvent tolerant, NADH-dependent medium-chain secondary alcohol dehydrogenase (denoted sec-ADH "A") from Rhodococcus ruber DSM 44541 is reported. The enzyme can withstand elevated concentrations of organic solvents, such as acetone (up to 50% v/v) and 2-propanol (up to 80% v/v). Thus, it is ideally suited for the preparative-scale enantioselective oxidation of sec-alcohol and the asymmetric reduction of ketones, using acetone and 2-propanol, respectively, as cosubstrates for cofactor-regeneration via a coupled-substrate approach. The homodimeric protein was found to bear tightly bound zinc and displayed a molecular mass of 38 kDa per subunit as determined by SDS gel electrophoresis. The optimal temperature ranged from 30-50 degrees C and the half-life at 50 degrees C was 35 h. In addition, excellent storage stability was found. The pH optimum for reduction is pH 6.5; pH 9.0 is preferred for oxidation. The enzyme followed a sequential reaction mechanism. The substrates are medium chain sec-alcohols or (omega-1)-ketones; primary alcohols or aldehydes are not accepted.     

Purification and characterization of aminopropionaldehyde dehydrogenase from Arthrobacter sp. TMP-1

Aminopropionaldehyde dehydrogenase was purified to apparent homogeneity from 1,3-diaminopropane-grown cells of Arthrobacter sp. TMP-1. The native molecular mass and the subunit molecular mass of the enzyme were approximately 20,5000 and 52,000, respectively, suggesting that the enzyme is a tetramer of identical subunits. The apparent Michaelis constant (K(m)) for 1,3-diaminopropane was approximately 3 microM. The enzyme equally used both NAD(+) and NADP(+) as coenzymes. The apparent K(m) values for NAD(+) and NADP(+) were 255 microM and 108 microM, respectively. The maximum reaction rates (V(max)) for NAD(+) and NADP(+) were 102 and 83.3 micromol min(-1) mg(-1), respectively. Some tested aliphatic aldehydes and aromatic aldehydes were inert as substrates. The optimum pH was 8.0-8.5. The enzyme was sensitive to sulfhydryl group-modifying reagents.     

Optimization of laccase production by Botryosphaeria sp. in the presence of veratryl alcohol by the response-surface method

Botryosphaeria sp. produced two laccases (PPO-I and PPO-II) constitutively, whose titers were enhanced by veratryl alcohol. The effect of veratryl alcohol and yeast extract concentration, time of cultivation and agitation speed were evaluated by factorial analysis to select variables for optimizing the production of laccases. Maximal laccase production was determined using a second-order central-composite design and analyzed by the response-surface method. Veratryl alcohol concentration and time of cultivation were the main factors increasing laccase production, while yeast extract had no influence within the range 0.2–2.0% w/v. Response-surface analysis showed that 30.4 mM veratryl alcohol, for 4.5 days at 28°C and 180 rpm, were the optimal conditions to maximize PPO-I production, while conditions for maximal PPO-II production occurred within a range of 28–35 mM veratryl alcohol over a growth period of 4–5.5 days. The model predicted 5.6 U ml⁻¹ for PPO-I, and 0.6–1.0 U ml⁻¹ for PPO-II, which agreed with the experimentally observed results.     

Thermostable phenylalanine dehydrogenase from a mesophilic Microbacterium sp. strain DM 86-1

Bacteria that produced NAD⁺-dependent phenylalanine dehydrogenase (EC 1.4.1.20) were selected among l-methionine utilizers isolated from soil. A bacterial strain showing phenylalanine dehydrogenase activity was chosen and classified in the genus Microbacterium. Phenylalanine dehydrogenase was purified from the crude extract of Microbacterium sp. strain DM 86-1 (TPU 3592) to homogeneity as judged by SDS-polyacrylamide disc gel electrophoresis. The enzyme has an isoelectric point of 5.8 and a relative molecular weight (M _r) of approximately 330,000. The enzyme is composed of eight identical subunits with an M _r of approximately 41,000. The apparent K _m values for l-phenylalanine and NAD⁺ were calculated to be 0.10 mM and 0.20 mM, respectively. No loss of the enzyme activity was observed upon incubation at 55° C for 10 min. Received: 30 July 1997 / Accepted: 4 November 1997     

Apo and Holo structures of an NADPH-dependent cinnamyl alcohol dehydrogenase from Saccharomyces cerevisiae

The crystal structure of Saccharomyces cerevisiae ScAdh6p has been solved using the anomalous signal from the two zinc atoms found per subunit, and it constitutes the first structure determined from a member of the cinnamyl alcohol dehydrogenase family. ScAdh6p subunits exhibit the general fold of the medium-chain dehydrogenases/reductases (MDR) but with distinct specific characteristics. In the three crystal structures solved (two trigonal and one monoclinic), ScAdh6p molecules appear to be structural heterodimers composed of one subunit in the apo and the second subunit in the holo conformation. Between the two conformations, the relative disposition of domains remains unchanged, while two loops, Cys250-Asn260 and Ile277-Lys292, experience large movements. The apo-apo structure is disfavoured because of steric impairment involving the loop Ile277-Lys292, while in the holo-holo conformation some of the hydrogen bonds between subunits would break apart. These suggest that the first NADPH molecule would bind to the enzyme much more tightly than the second. In addition, fluorimetric analysis of NADPH binding demonstrates that only one cofactor molecule binds per dimer. Therefore, ScAdh6p appears to function according to a half-of-the-sites reactivity mechanism, resulting from a pre-existing (prior to cofactor binding) tendency for the structural asymmetry in the dimer. The specificity of ScAdh6p towards NADPH is mainly due to the tripod-like interactions of the terminal phosphate group with Ser210, Arg211 and Lys215. The size and the shape of the substrate-binding pocket correlate well with the substrate specificity of ScAdh6p towards cinnamaldehyde and other aromatic compounds. The structural relationships of ScAdh6p with other MDR structures are analysed.     

The structure of an alcohol dehydrogenase from the hyperthermophilic archaeon Aeropyrum pernix

The structure of the recombinant medium chain alcohol dehydrogenase (ADH) from the hyperthermophilic archaeon Aeropyrum pernix has been solved by the multiple anomalous dispersion technique using the signal from the naturally occurring zinc ions. The enzyme is a tetramer with 222 point group symmetry. The ADH monomer is formed from a catalytic and a cofactor-binding domain, with the overall fold similar to previously solved ADH structures. The 1.62 A resolution A.pernix ADH structure is that of the holo form, with the cofactor NADH bound into the cleft between the two domains. The electron density found in the active site has been interpreted to be octanoic acid, which has been shown to be an inhibitor of the enzyme. This inhibitor is positioned with its carbonyl oxygen atom forming the fourth ligand of the catalytic zinc ion. The structural zinc ion of each monomer is present at only partial occupancy and in its absence a disulfide bond is formed. The enhanced thermal stability of the A.pernix ADH is thought to arise primarily from increased ionic and hydrophobic interactions on the subunit interfaces.     

Distribution of aldehyde dehydrogenase and alcohol dehydrogenase in summer-acclimatized crucian carp, Carassius carassius L.

The tissue distribution of aldehyde dehydrogenase (ALDH) and alcohol dehydrogenase (ADH) in summer-acclimatized crucian carp showed almost the same exceptional pattern as previously found in winter-acclimatized specimens. There was a nearly complete spatial separation of ALDH and ADH; in other vertebrates these enzymes occur together. This exceptional enzyme distribution is probably an adaptation to the extraordinary ability of Carassius to produce ethanol as the major metabolic end product during anoxia. Since the crucian carp is less likely to encounter anoxia during the summer, the present results suggest that the crucian carp is unable to switch over to a 'normal' ALDH and ADH distribution in the summer. However, it is also possible that there is an advantage for the summer-acclimatized crucian carp in keeping ALDH and ADH separate, because of occasional anoxic periods.