scholarly journals Role of the essential thiol groups of yeast alcohol dehydrogenase

1972 ◽  
Vol 126 (1) ◽  
pp. 133-138 ◽  
Author(s):  
F. M. Dickinson
Keyword(s):  
Alcohol Dehydrogenase ◽  
Dissociation Constant ◽  
Binding Capacity ◽  
Ternary Complexes ◽  
Native Enzyme ◽  
Thiol Groups ◽  
Yeast Alcohol Dehydrogenase

1. Yeast alcohol dehydrogenase inactivated by reaction with iodoacetamide retains 85% of the original NADH-binding capacity as measured under conditions of saturating coenzyme concentration. 2. The dissociation constant of the enzyme–NADH complex is unaffected by inactivation of the enzyme with iodoacetamide, and the affinity of the enzyme for NAD+ and pyridine-3-aldehyde–adenine dinucleotide (PAAD+) appears to be similarly unaffected. 3. Enzyme inactivated with iodoacetamide has lost the ability to form normal ternary complexes of the type enzyme–NADH–acetamide and enzyme–PAAD+–hydroxylamine that are characteristic of the native enzyme.

scholarly journals A study of the ionic properties of the essential histidine residue of yeast alcohol dehydrogenase in complexes of the enzyme with its coenzymes and substrates

1977 ◽  
Vol 161 (1) ◽  
pp. 73-82 ◽  
Author(s):  
C J Dickenson ◽  
F M Dickinson
Keyword(s):  
Alcohol Dehydrogenase ◽  
Initial Rate ◽  
Dissociation Constants ◽  
Ternary Complexes ◽  
Histidine Residue ◽  
Mechanism Of Formation ◽  
Binary And Ternary Complexes ◽  
Yeast Alcohol Dehydrogenase ◽  
Ph Range

1. Initial-rate studies of the reduction of acetaldehyde by NADH, catalysed by yeast alcohol dehydrogenase, were performed at pH 4.9 and 9.9, in various buffers, at 25 degrees C. The results are discussed in terms of the mechanism previously proposed for the pH range 5.9-8.9 [Dickenson & Dickinson (1975) Biochem. J. 147, 303-311]. 2. Acetaldehyde forms a u.v.-absorbing complex with glycine. This was shown not to affect the results of kinetic experiments under the conditions used in this and earlier work. 3. The variation with pH of the dissociation constant for the enzyme-NADH complex, calculated from the initial-rate data, indicates that the enzyme possesses a group with pK7.1 in the free enzyme and pK8.7 in the complex. 4. The pH-dependences of the second-order rate constants for inactivation of the enzyme by diethyl pyrocarbonate were determined for the free enzymes (pK7.1), the enzyme-NAD+ complex (pK approx. 7.1) and the enzyme-NADH complex (pK approx. 8.4). The essential histidine residue may therefore be the group involved in formation and dissociation of the enzyme-NADH complex. 5. Estimates of the rate constant for reaction of acetaldehyde with the enzyme-NADH complex indicate that acetaldehyde may combine only when the essential histidine residue is protonated. The dissociation constants for butan-1-ol and propan-2-ol, calculated on the basis of earlier kinetic data, are, however, independent of pH. 6. The results obtained are discussed in relation to the role of the essential histidine residue in the mechanism of formation of binary and ternary complexes of the enzyme with its coenzymes and substrates.

scholarly journals The reactions of 1,10-phenanthroline with yeast alcohol dehydrogenase

1977 ◽  
Vol 167 (1) ◽  
pp. 237-244 ◽  
Author(s):  
F M Dickinson ◽  
S Berrieman
Keyword(s):  
Alcohol Dehydrogenase ◽  
Complete Recovery ◽  
Ternary Complexes ◽  
Second Step ◽  
Two Stage ◽  
Reversible Process ◽  
Structural Role ◽  
Yeast Alcohol Dehydrogenase ◽  
Stage Process

Freshly prepared samples of yeast alcohol dehydrogenase (EC 1.1.1.1) were inhibited by 1,10-phenanthroline at pH 7.0 and 0 degrees C in a two-stage process. The first step appeared to be slowly established, but was rendered reversible by removal of reagent or by addition of excess Zn2+ ions. The second step was irreversible and was associated with the dissociation of the tetrameric enzyme. The presence of saturating concentrations of NAD+ or NADH promoted and enhanced inhibition by the slowly established reversible process, but prevented dissociation of the enzyme. For the incubation mixtures containing NAD+, removal of the 1,10-phenanthroline resulted in virtually complete recovery of activity, whereas, for the incubation mixtures containing NADH, removal of the reagent gave only partial re-activation. The presence of NAD+ and pyrazole, or NADH and acetamide, in incubation mixtures with the enzyme gave rise to ternary complexes that gave protection against both forms of inactivation by 1,10-phenanthroline. The results support the view that at least some of the Zn2+ ions associated with yeast alcohol dehydrogenase have a catalytic, as opposed to a purely structural, role.

scholarly journals A study of the oxidation of butan-1-ol and propan-2-ol by nicotinamide-adenine dinucleotide catalysed by yeast alcohol dehydrogenase.

1975 ◽  
Vol 147 (3) ◽  
pp. 541-547 ◽  
Author(s):  
C J Dickenson ◽  
F M Dickinson
Keyword(s):  
Alcohol Dehydrogenase ◽  
Ternary Complexes ◽  
Kinetics Of Oxidation ◽  
Yeast Alcohol Dehydrogenase ◽  
Rate Limiting Step ◽  
Limiting Step ◽  
Ph Range ◽  
Rate Limiting ◽  
Kinetics Of ◽  
Flow Experiments

1. The kinetics of oxidation of butan-1-ol and propan-2-ol by NAD+, catalysed by yeast alcohol dehydrogenase, were studied at 25 degrees C from pH 5.5 to 10, and at pH 7.05 from 14 degrees to 44 degrees C, 2. Under all conditions studied the results are consistent with a mechanism whereby some dissociation of coenzyme from the active enzyme-NAD+-alcohol ternary complexes occurs, and the mechanism is therefore not strictly compulsory order. 3. A primary 2H isotopic effect on the maximum rates of oxidation of [1-2H2]butan-1-ol and [2H7]propan-2-ol was found at 25 degrees C over the pH range 5.5-10. Further, in stopped-flow experiments at pH 7.05 and 25 degrees C, there was no transient formation of NADH in the oxidation of butan-1-ol and propan-2-ol. The principal rate-limiting step in the oxidation of dependence on pH of the maximum rates of oxidation of butan-1-ol and propan-2-ol is consisten with the possibility that histidine and cysteine residues may affect or control catalysis.

scholarly journals The thiol groups of yeast alcohol dehydrogenase

1964 ◽  
Vol 90 (3) ◽  
pp. 532-539 ◽  
Author(s):  
EP Whitehead ◽  
BR Rabin
Keyword(s):  
Alcohol Dehydrogenase ◽  
Thiol Groups ◽  
Yeast Alcohol Dehydrogenase

Role of metal ions to specific binding of yeast alcohol dehydrogenase by free and immobilized dyes

1983 ◽  
Vol 79 ◽  
pp. 157-158
Author(s):  
S.S. Flaksaite ◽  
O.F. Sudzhiuvene ◽  
J.-H. J. Pesliakas ◽  
A.A. Glemzha
Keyword(s):  
Alcohol Dehydrogenase ◽  
Metal Ions ◽  
Specific Binding ◽  
Yeast Alcohol Dehydrogenase

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.

scholarly journals A study of the kinetics and mechanism of yeast alcohol dehydrogenase with a variety of substrates

1973 ◽  
Vol 131 (2) ◽  
pp. 261-270 ◽  
Author(s):  
F. M. Dickinson ◽  
G. P. Monger
Keyword(s):  
Alcohol Dehydrogenase ◽  
Ethanol Oxidation ◽  
Ternary Complexes ◽  
Kinetics Of Oxidation ◽  
Yeast Alcohol Dehydrogenase ◽  
Rate Limiting Step ◽  
Limiting Step ◽  
Binary Complexes ◽  
Rate Limiting ◽  
Kinetics Of

1. The kinetics of oxidation of ethanol, propan-1-ol, butan-1-ol and propan-2-ol by NAD+ and of reduction of acetaldehyde and butyraldehyde by NADH catalysed by yeast alcohol dehydrogenase were studied. 2. Results for the aldehyde–NADH reactions are consistent with a compulsory-order mechanism with the rate-limiting step being the dissociation of the product enzyme–NAD+ complex. In contrast the results for the alcohol–NAD+ reactions indicate that some dissociation of coenzyme from the active enzyme–NAD+–alcohol ternary complexes must occur and that the mechanism is not strictly compulsory-order. The rate-limiting step in ethanol oxidation is the dissociation of the product enzyme–NADH complex but with the other alcohols it is probably the catalytic interconversion of ternary complexes. 3. The rate constants describing the combination of NAD+ and NADH with the enzyme and the dissociations of these coenzymes from binary complexes with the enzyme were measured.

Sign in / Sign up

Export Citation Format

Share Document