The Equilibrium Constant of the System Ethanol, Aldehyde, DPN+, DPNH and H+.

Bäcklin, Karl-Ingemar; Studnitz, W. von; Bergson, Göran; Grönvall, A.; Zaar, B.; Diczfalusy, E.

doi:10.3891/acta.chem.scand.12-1279

Cited by 73 publications

(11 citation statements)

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“…The equilibrium constants calculated using the Haldane equation, K eq = ( V 1 K p K iq [H + ])/( V 2 K b K ia ), are similar to the established value of 12 pM at 30 °C [50]. …”

Section: Figures and Tablessupporting

confidence: 70%

Activity of yeast alcohol dehydrogenases on benzyl alcohols and benzaldehydes

Pal

Park

Plapp

2009

Chemico-Biological Interactions

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The substrate specificities of yeast alcohol dehydrogenases I and II from Saccharomyces cerevisiae (SceADH1 and SceADH2) and Saccharomyces carlsbergensis (ScbADH1) were studied. For this work, the gene for the S. carlsbergensis ADH1 was cloned, sequenced and expressed. The amino acid sequence of ScbADH1 differs at four positions as compared to SceADH1, including substitutions of two glutamine residues with glutamic acid residues, and has the same sequence as the commercial yeast enzyme, which apparently is prepared from S. carlsbergensis. The electrophoretic mobilities of ScbADH1, SceADH2 and commercial ADH are similar. The kinetics and specificities of ScbADH1 and SceADH1 acting on branched, long-chain and benzyl alcohols are very similar, but the catalytic efficiency of SceADH2 is about 10 to 100-fold higher on these substrates. A three dimensional structure of SceADH1 shows that the substrate binding pocket has Met-270, whereas SceADH2 has Leu-270, which allows larger substrates to bind. The reduction of a series of p-substituted benzaldehydes catalyzed by SceADH2 is significantly enhanced by electronwithdrawing groups, whereas the oxidation of p-substituted aromatic alcohols may be only slightly affected by the substituents. The substituent effects on catalysis generally reflect the effects on the equilibrium constant for the reaction, where electron-withdrawing substituents favor alcohol. The results are consistent with a transition state that is electronically similar to the alcohol, supporting previous results obtained with commercial yeast ADH.

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“…The equilibrium constants calculated using the Haldane equation, K eq = ( V 1 K p K iq [H + ])/( V 2 K b K ia ), are similar to the established value of 12 pM at 30 °C [50]. …”

Section: Figures and Tablessupporting

confidence: 70%

Activity of yeast alcohol dehydrogenases on benzyl alcohols and benzaldehydes

Pal

Park

Plapp

2009

Chemico-Biological Interactions

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“…The values ofKeq. at other temperatures were obtained by calculation from the value at 25°C by using AHO = 30kJ mol1 (Backlin, 1958 t Best results available based on this work and the earlier work of Dickinson & Monger (1973). those of Klinman (1972).…”

Section: Discussionmentioning

confidence: 82%

A study of the pH- and temperature-dependence of the reactions of yeast alcohol dehydrogenase with ethanol, acetaldehyde and butyraldehyde as substrates

Dickenson¹,

Dickinson²

1975

Biochemical Journal

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The kinetics of ethanol oxidation by NAD+, and acetaldehyde and butyraldehyde reduction by NADH, catalysed by yeast alcohol dehydrogenase, were studied in the pH range 4.9--9.9 at 25 degrees C and in the temperature range 14.8--43.5 degrees C at pH 7.05. The kinetics of reduction of acetaldehyde by [4A-2H]NADH at pH 7.05 and pH 8.9 at 25 degrees C were also studied. The results of the kinetic experiments indicate that the mechanism of catalysis, previously proposed on the basis of studies at pH 7.05 and 25 degrees C (Dickinson & Monger, 1973), applies over the wide range of conditions now tested. Values of some of the initial-rate parameters obtained were used to deduce information about the pH- and temperature-dependence of the specific rates of combination of enzyme and coenzymes and of the dissociation of the enzyme--coenzyme compounds. Primary and secondary plots of initial-rate data are deposited as Supplementary Publication SUP 50043 (20 pages) with the British Library (Lending Division), Boston Spa, Wetherby, Yorks. LS23 7BQ, U.K., from whom copies may be obtained under the terms indicated in Biochem. J. (1975) 145, 5.

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“…7. Furthermore, the equilibrium of the reaction is unfavourable for precise spectrophotometric initial-rate measurements of ethanol oxidation at pH7 (Backlin, 1958), particularly in the presence of acetaldehyde and with relatively low concentrations of ethanol. It is concluded that the results of Wratten & Cleland (1963) are probably compatible with those reported here.…”

Section: K_4mentioning

confidence: 99%

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

Dickenson¹,

Dickinson²

1978

Biochemical Journal

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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.

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The Equilibrium Constant of the System Ethanol, Aldehyde, DPN+, DPNH and H+.

Cited by 73 publications

References 0 publications

Activity of yeast alcohol dehydrogenases on benzyl alcohols and benzaldehydes

Activity of yeast alcohol dehydrogenases on benzyl alcohols and benzaldehydes

A study of the pH- and temperature-dependence of the reactions of yeast alcohol dehydrogenase with ethanol, acetaldehyde and butyraldehyde as substrates

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

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