Covalently anchoring of a ligand/metal via polar amino acid side chain(s) is often observed in metalloenzyme, while the substitutability of metal-binding sites remains elusive. In this study, we utilized a zinc-dependent alcohol dehydrogenase from Thermoanaerobacter brockii (TbSADH) as a model enzyme, analyzed the sequence conservation of the three residues Cys37, His59, and Asp150 that bind the zinc ion, and constructed the mutant library. After experimental validation, three out of 224 clones, which showed comparative conversion and ee values as the wild-type enzyme in the asymmetric reduction of the model substrate tetrahydrofuran-3-one, were screened out. The results reveal that the metal-binding sites in TbSADH are substitutable without tradeoff in activity and stereoselectivity, which lay a foundation for designing ADH-catalyzed new reactions via metal ion replacement.
Alcohol Dehydrogenase/metabolism* ; Catalytic Domain ; Ligands ; Protein Domains ; Zinc/metabolism*

To evaluate the concentration-time profiles of breath ethanol in degradation phase in proportion to the amount of alcohol, we carried out the controlled drinking study for 24 healthy males. Studies are performed three times in the interval of two weeks. Before the experiment, we analyzed alcohol dehydrogenase (ADH) and aldehyde dehydrogenase (ALDH) to compare with the degradation rate. All subjects are classified into three groups considering past alcohol-drinking history. Group A subjects (n = 6) consumed 0.25, 0.5 and 0.75 g ethanol kg of body weight, group B subjects (n = 9) 0.5, 0.75 and 1.0 g, and group C subjects (n = 9) 0.75, 1.0 and 1.25 g in fasting state, respectively. Breath alcohol samples were examined from 30 minutes to 5 hour every 30-60 minutes after the alcohol intake. Statistical analysis of breath alcohol concentration (BrAC) values obtained. Concentration-time profiles of alcohol were plotted for each subject and the rate of degradation of breath was determined using linear regression analysis. According to the mean of corrected regression lines, disappearance rate of BrAC is calculated in A group: 0.0101 +/- 0.000232% (v/v), B group: 0.0093 +/- 0.000133% (v/v), C group: 0.0099 +/- 0.000121% (v/v).
Alcohol Dehydrogenase ; Aldehyde Dehydrogenase ; Body Weight ; Drinking ; Ethanol ; Fasting ; Humans ; Linear Models ; Male

The protective effect of EtOAc fraction of Limonium tetragonum extract (EALT) against alcoholinduced hepatotoxicity was assessed following acute ethanol intoxication in Spraque-Dawley rats. EALT (200 mg/kg p.o.) was administrated once before alcohol intake (8 g/kg, p.o.). Blood ethanol concentration, and the activities of alcohol metabolic enzymes, alcohol dehydrogenase (ADH) and aldehyde dehydrogenase (ALDH) in the liver were measured. Also, the formation of malondialdehyde (MDA) and the activities of antioxidant enzymes, superoxide dismutase (SOD), glutathione peroxidase (GSH-px), catalase were determined after acute alcohol exposure. Pretreatment of rats received ethanol with EALT significantly decreased blood ethanol concentration and elevated the activities of ADH and ALDH in liver. The increased MDA level was decreased, and the reduced activities of SOD, GSH-px and catalase were markedly preserved by the treatment with EALT. This study suggests that EALT prevent hepatic injury induced by acute alcohol which is likely related to its modulation on the alcohol metabolism and antioxidant enzymes activities.
Alcohol Dehydrogenase ; Aldehyde Dehydrogenase ; Animals ; Catalase ; Ethanol* ; Glutathione Peroxidase ; Liver* ; Malondialdehyde ; Metabolism* ; Plumbaginaceae* ; Rats ; Salt-Tolerant Plants ; Superoxide Dismutase

Aldehyde dehydrogenase 2 (ALDH2), as one of the most important alcohol metabolizing enzymes, plays a significant role in the detoxification process of acetaldehyde which is a main carcinogenic product of alcoholic metabolism. Alteration in its genotypes (particularly at the site of rs671) is closely associated with a variety of tumors in drinkers. Recent advance in the research of the association of the ALDH2 gene rs671 polymorphisms with cancer susceptibility in drinkers is reviewed.
Alcohol Drinking ; genetics ; Aldehyde Dehydrogenase ; genetics ; Aldehyde Dehydrogenase, Mitochondrial ; Genetic Predisposition to Disease ; Humans ; Neoplasms ; etiology ; genetics ; Polymorphism, Genetic

OBJECTIVE: To explore alcohol pharmacokinetics as well as acetaldehyde level in peripheral blood in human subjects with different ALDH2 genotypes after drinking. METHODS: Venous blood samples of 14 unrelated volunteers were collected. Polymerase chain reaction-restriction fragment length polymorphism technology was adopted for DNA extraction and ALDH2 genotyping. The volunteers were asked to drink beer at certain doses. The concentration of alcohol and acetaldehyde were assayed by headspace gas chromatography method at different time. The pharmacokinetic parameters were calculated. RESULTS: According to the results of electrophoresis, 5 people carried ALDH2*1/*1 as wild group and 9 people carried ALDH2*1/*2 as mutation group. The good linear range of alcohol and acetaldehyde were 0-1 570.7 microg/mL and 0-5.1772 microg/mL, respectively. The AUC values of alcohol and acetaldehyde and the t1/2Z value of alcohol were higher in the mutation group than that in the wild group. But the CL/F value of alcohol was lower in the mutation group than that in the wild group (P<0.05). CONCLUSION After the consumption of alcohol, alcohol and acetaldehyde metabolism in blood slow down in ALDH2*1/*2 mutation group influenced by the inhibition of enzyme activity, leading to the accumulation of acetaldehyde in peripheral blood, thus reinforcing their effects in the body.
Alcohol Drinking ; Aldehyde Dehydrogenase/genetics* ; Aldehyde Dehydrogenase, Mitochondrial ; Ethanol/metabolism* ; Genotype ; Humans ; Polymerase Chain Reaction ; Polymorphism, Genetic

Bacillus sp. TSH1 is a butanol-producing microorganism newly isolated in our laboratory; it can grow and ferment under facultative anaerobic conditions, while sharing similar fermentation pathways and products with Clostridium acetobutylicum. To illustrate the relationships between the products and the enzyme activities in Bacillus sp. TSH1, key butanol- and ethanol-forming enzymes were studied, including butyraldehyde dehydrogenase, butanol dehydrogenase and alcohol dehydrogenase. The activities of the three enzymes increased rapidly after the initiation of fermentation. Activities of three enzymes peaked before 21 h, and simultaneously, product concentrations also began to increase gradually. The maximum activity of alcohol dehydrogenase was 0.054 U/mg at 12 h, butyraldehyde dehydrogenase 0.035 U/mg at 21 h and butanol dehydrogenase 0.055 U/mg at 15 h. The enzyme activities then decreased, but remained constant at a low level after 24 h, while the concentrations of butanol, acetone, and ethanol continued increasing until the end of the fermentation. The results will attribute to the understanding of the butanol metabolic mechanism, and provide a reference for further study of a facultative Bacillus metabolic pathway.
Alcohol Dehydrogenase ; metabolism ; Alcohol Oxidoreductases ; metabolism ; Aldehyde Oxidoreductases ; metabolism ; Anaerobiosis ; Bacillus ; classification ; genetics ; metabolism ; Butanols ; metabolism ; Fermentation ; Metabolic Networks and Pathways

Ethylene glycol poisoning is treated mainly by alcohol dehydrogenase inhibition therapy and hemodialysis. Early recognition and initiation of treatment is important because toxic metabolites increase over time by hepatic metabolism; however, there is no confirmative diagnostic tool in our clinical setting. Therefore, diagnosis is dependent on history, high anion gap acidosis, high osmolal gap, etc.. Diagnosis and treatment are delayed in cases where history taking is not possible, such as a mental changed patient. Authors report on two cases of ethylene glycol poisoning by contrasting clinical outcomes, demonstrating the importance of early diagnosis and treatment for achievement of a good outcome.
Achievement ; Acid-Base Equilibrium ; Acidosis ; Alcohol Dehydrogenase ; Early Diagnosis ; Ethylene Glycol ; Ethylenes ; Osmolar Concentration ; Renal Dialysis

Objective To explore the change rules of blood ethanol and blood acetaldehyde concentration, the impairment of psychomotor functions of different acetaldehyde dehydrogenase （ALDH） 2 genotype individuals after alcohol consumption and the relationship among them. Methods The ALDH2 genotypes in seventy-nine healthy volunteers were obtained by SNaPshot^TM method, then divided into ALDH2*1/*1 （wild type） and ALDH2*1/*2 （mutant type） group. After volunteers consumed 1.0 g/kg of alcohol, blood ethanol concentration and blood acetaldehyde concentration at a series of time points before and after alcohol consumption and psychomotor functions, such as, visual selective response time, auditory simple response time and tracking experiment were detected. Biphasic alcohol response questionnaires were collected. Results After alcohol consumption, ALDH2*1/*2 group's blood ethanol and blood acetaldehyde concentration reached the peak earlier than ALDH2*1/*1 group. Its blood acetaldehyde concentration was higher than that of ALDH2*1/*1 group, 1-6 h after alcohol consumption. The psychomotor functions, such as visual selective response time and auditory simple response time in ALDH2*1/*2 group were more significantly impaired than those in ALDH2*1/*1 group after alcohol consumption. There was no statistical significance between the two groups in excitement or sedation reactions （P>0.05）. Pearson correlation coefficient test showed that blood acetaldehyde concentration was related with psychomotor function. Conclusion There are significant differences between the psychomotor function of ALDH2 wild type and mutant type individuals after alcohol consumption estimated to be related to the difference in blood acetaldehyde concentration after alcohol consumption.
Acetaldehyde/metabolism* ; Alcohol Drinking/blood* ; Aldehyde Dehydrogenase/genetics* ; Aldehyde Dehydrogenase, Mitochondrial ; Aldehyde Oxidoreductases ; Ethanol/metabolism* ; Genotype ; Humans ; Polymorphism, Genetic/genetics* ; Psychomotor Performance/physiology*

Through studying the process of glycerol fermentation to 1, 3-propanediol(1, 3-PD) by Klebsiella pneumoniae, it was found that the cell growth and product (or by-product) production were under salt stress. Cell growth and product formation kept high rate at low salt concentration. High salt concentration led to low growth of cells, final concentration of 1, 3-PD and conversion from glycerol to 1, 3-PD, and, 1, 3-propanediol oxidoreductase activity decreased. When the salt concentration in 5 m3 bioreactor was controlled under appropriate manner, the concentration of 1, 3-PD production was markedly enhanced. The final 1, 3-PD concentration ,the conversion of glycerol to 1, 3-PD and productivity were 64 g/L, 61% and 2.1 g/(L x h).
Alcohol Dehydrogenase ; Alcohol Oxidoreductases ; metabolism ; Culture Media ; Culture Techniques ; Fermentation ; Glycerol ; metabolism ; Klebsiella pneumoniae ; growth & development ; metabolism ; physiology ; Propylene Glycols ; metabolism ; Sodium Chloride ; pharmacology ; Stress, Physiological

The kinetic mechanisms of two key enzymes in the biotransformation of glycerol to 1,3-propanediol (1,3-PD) by Klebsiella pneumoniae, glycerol dehydrogenase (GDH) and 1,3-propanediol oxidoreductase (PDOR), was characterized. Kinetics on initial velocity and product inhibition revealed that GDH and PDOR follow an ordered Bi-Bi sequential mechanism. Kinetic models for GDH and PDOR showed that the oxidation reaction catalyzed by GDH was the rate-limiting step in coupled enzymatic reaction when the GDH/PDOR was 1:1, and the NAD+ was the main form of coenzyme in the reaction. Knowledge about the kinetic mechanisms will be helpful to understand how these enzymes is regulated, which will be useful for further enzyme catalysis and metabolic engineering studies.
Alcohol Dehydrogenase ; metabolism ; Bacterial Proteins ; metabolism ; Glycerol ; metabolism ; Kinetics ; Klebsiella pneumoniae ; enzymology ; Models, Theoretical ; Propylene Glycols ; metabolism ; Substrate Specificity ; Sugar Alcohol Dehydrogenases ; metabolism