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

1978 ◽  
Vol 171 (3) ◽  
pp. 613-627 ◽  
Author(s):  
C J Dickenson ◽  
F M Dickinson
Keyword(s):  
Alcohol Dehydrogenase ◽  
Dissociation Constant ◽  
Maximum Rate ◽  
Alternative Pathway ◽  
Product Inhibition ◽  
Experimental Conditions ◽  
Alcohol Dehydrogenases ◽  
Yeast Alcohol Dehydrogenase ◽  
Liver Alcohol Dehydrogenase ◽  
Horse Liver

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.

Interaction between horse liver alcohol dehydrogenase and aporphine alkaloids

1982 ◽  
Vol 47 (1) ◽  
pp. 296-303 ◽  
Author(s):  
Daniela Walterová ◽  
Jan Kovář ◽  
Vladimír Preininger ◽  
Vilím Šimánek
Keyword(s):  
Alcohol Dehydrogenase ◽  
Dissociation Constant ◽  
Active Center ◽  
Inhibitory Effect ◽  
Horse Liver Alcohol Dehydrogenase ◽  
Liver Alcohol Dehydrogenase ◽  
Horse Liver ◽  
Fluorescence Methods

The interaction between horse liver alcohol dehydrogenase (ADH) and aporphine alkaloids has been studied by kinetic and fluorescence methods. The aporphine alkaloids inhibit ADH. The inhibitory effect depends on the position and type of the substituents in the aporphine nucleus. Aporheine shows the strongest binding to the enzyme, and that irrespective of the configuration of the molecule. The dissociation constant of the complex enzyme-aporpheine is 20-25μmol l-1. The results indicate that the aporphine alkaloids bind to the active center of alcohol dehydrogenase with stechiometry 1 : 1.

Methylamine adenine dinucleotide (MAD): a co-factor to turn alcohol dehydrogenases into aldolases

2002 ◽  
Vol 80 (6) ◽  
pp. 665-670 ◽  
Author(s):  
Denis Wahler ◽  
Jean-Louis Reymond
Keyword(s):  
Alcohol Dehydrogenase ◽  
Active Site ◽  
Primary Amine ◽  
Adenosine Monophosphate ◽  
Chemoenzymatic Synthesis ◽  
Penicillin G ◽  
Alcohol Dehydrogenases ◽  
Horse Liver Alcohol Dehydrogenase ◽  
Liver Alcohol Dehydrogenase ◽  
Horse Liver

Methylamine adenine dinucleotide (MAD) was prepared in seven steps and 15.3% overall yield from 1-acetoxy-2,3,5-tri-O-benzoyl-D-ribose by chemoenzymatic synthesis. The key step was the phosphate–phosphate coupling between adenosine monophosphate and 2,5-anhydro-1-deoxy-1-phenylacetamide-6-phosphate-D-allitol (3) mediated by carbonyl diimidazole (CDI), followed by the removal of the phenylacetamido group by penicillin G acylase. The MAD co-factor provided a primary amine functionality that was suitably positioned to promote the enamine aldolization of 2-oxopropionamide with aldehydes within the active site of alcohol dehydrogenases, which should lead to the transformation of these stereoselective enzymes into aldolases. Preliminary investigations did not reveal any activity with horse liver alcohol dehydrogenase or yeast alcohol dehydrogenase.Key words: aldolases, alcohol dehydrogenases, co-factor enginering, nucleosides, acylases.

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