scholarly journals Studies on the interaction between disulfiram and sheep liver cytoplasmic aldehyde dehydrogenase

1978 ◽  
Vol 175 (1) ◽  
pp. 83-90 ◽  
Author(s):  
T M Kitson
Keyword(s):  
Enzyme Activity ◽  
Linear Relationship ◽  
Dehydrogenase Activity ◽  
Aldehyde Dehydrogenase ◽  
Esterase Activity ◽  
Competitive Inhibitor ◽  
Enzyme Molecule ◽  
Covalent Interaction ◽  
Sheep Liver ◽  
Non Linear

The effect of disulfiram, [1-14C]disulfiram and some other thiol reagents on the activity of cytoplasmic aldehyde dehydrogenase from sheep liver was studied. The results are consistent with a rapid covalent interaction between disulfiram and the enzyme, and inconsistent with the notion that disulfiram is a reversible competitive inhibitor of cytoplasmic aldehyde dehydrogenase. There is a non-linear relationship between loss of about 90% of the enzyme activity and amount of disulfiram added; possible reasons for this are discussed. The remaining approx. 10% of activity is relatively insensitive to disulfiram. It is found that modification of only a small number of groups (one to two) per tetrameric enzyme molecule is responsible for the observed loss of activity. The dehydrogenase activity of the enzyme is affected more severely by disulfiram than is the esterase activity. Negatively charged thiol reagents have little or no effect on cytoplasmic aldehyde dehydrogenase. 2,2′-Dithiodipyridine is an activator of the enzyme.

scholarly journals Effect of some thiocarbamate compounds on aldehyde dehydrogenase and implications for the disulfiram ethanol reaction

1991 ◽  
Vol 278 (1) ◽  
pp. 189-192 ◽  
Author(s):  
T M Kitson
Keyword(s):  
Dehydrogenase Activity ◽  
Aldehyde Dehydrogenase ◽  
Esterase Activity ◽  
Negligible Effect ◽  
Weak Inhibitor ◽  
Low Concentration ◽  
The Third ◽  
Sheep Liver ◽  
Physiological Phenomenon

The effects of S-methyl diethyldithiocarbamate, S-methyl diethylmonothiocarbamate and bis(diethylcarbamoyl) disulphide on sheep liver cytoplasmic aldehyde dehydrogenase were investigated in vitro. The first compound has negligible effect. The second one is a weak inhibitor of the esterase activity of the enzyme and a weaker inhibitor of the dehydrogenase activity. A very low concentration of the third compound, however, acts as a potent inactivator of aldehyde dehydrogenase, similar in this respect to disulfiram, although somewhat slower to react. The possible involvement of these compounds in the physiological phenomenon known as the disulfiram ethanol reaction is discussed.

Bovine lens aldehyde dehydrogenase: Activity and non-linear steady-state kinetics

1986 ◽  
Vol 43 (2) ◽  
pp. 177-184 ◽  
Author(s):  
M. James ◽  
C. Crabbe ◽  
Robert M. Jordan ◽  
H.-H. Ting ◽  
Stephen T. Hoe
Keyword(s):  
Steady State ◽  
Dehydrogenase Activity ◽  
Aldehyde Dehydrogenase ◽  
Bovine Lens ◽  
Steady State Kinetics ◽  
Non Linear ◽  
Aldehyde Dehydrogenase Activity

scholarly journals The activation of aldehyde dehydrogenase by diethylstilboestrol and 2,2′-dithiodipyridine

1982 ◽  
Vol 207 (1) ◽  
pp. 81-89 ◽  
Author(s):  
T M Kitson
Keyword(s):  
Enzyme Activity ◽  
Aldehyde Dehydrogenase ◽  
Human Liver ◽  
Common Property ◽  
Rabbit Liver ◽  
Aldehyde Dehydrogenases ◽  
Cytoplasmic Enzyme ◽  
Sheep Liver ◽  
Low Concentrations ◽  
Liver Aldehyde Dehydrogenase

1. The activation of sheep liver cytoplasmic aldehyde dehydrogenase by diethylstilboestrol and by 2,2′-dithiodipyridine is described. The effects of the two modifiers are very similar with respect to variation with acetaldehyde concentration, pH and temperature. Thus the degree of activation is maximal when the enzyme is assayed at approx. 1 mM-acetaldehyde, is greater at 25 degrees C than at 37 degrees C, and is greater at pH 7.4 than at pH 9.75. With low concentrations of acetaldehyde both modifiers decrease the enzyme activity. 2. Diethylstilboestrol affects the sheep liver cytoplasmic enzyme in a very similar way to that previously described for a rabbit liver cytoplasmic enzyme. Preliminary experiments show that the same is true for a preparation of human liver aldehyde dehydrogenase. It is proposed that sensitivity to diethylstilboestrol (and steroids) is a common property of all mammalian cytoplasmic aldehyde dehydrogenases.

scholarly journals Effects of Mg2+, Ca2+ and Mn2+ on sheep liver cytoplasmic aldehyde dehydrogenase

1982 ◽  
Vol 205 (2) ◽  
pp. 443-448 ◽  
Author(s):  
F M Dickinson ◽  
G J Hart
Keyword(s):  
Aldehyde Dehydrogenase ◽  
Esterase Activity ◽  
Metal Ion ◽  
Stopped Flow ◽  
Maximal Effect ◽  
Ion Concentrations ◽  
Sheep Liver ◽  
High Concentrations ◽  
Flow Experiments ◽  
Active Centres

Sheep liver cytoplasmic aldehyde dehydrogenase is strongly inhibited by Mg2+, Ca2+ and Mn2+. The inhibition is only partial, however, with 8-15% of activity remaining at high concentrations of these agents. In 50 mM-Tris/Hcl, pH 7.5, the concentrations giving half-maximal effect were: Mg2+, 6.5 micrometers; Ca2+, 15.2 micrometers; Mn2+, 1.5 micrometer. The esterase activity of the enzyme is not affected by such low metal ion concentrations, but appears to be activated by high concentrations. Fluorescence-titration and stopped-flow experiments provide evidence for interaction of Mg2+ with NADH complexes of the enzyme. As no evidence for the presence of increased concentrations of functioning active centres was obtained in the presence of Mg2+, it is concluded that effects of Mg2+ (and presumably Ca2+ and Mn2+ also) are brought about by trapping increased concentrations of NADH in a Mg2+-containing complex. This complex must liberate products more slowly than any of the complexes involved in the non-inhibited mechanism.

scholarly journals The use of pH-gradient ion-exchange chromatography to separate sheep liver cytoplasmic aldehyde dehydrogenase from mitochondrial enzyme contamination, and observations on the interaction between the pure cytoplasmic enzyme and disulfiram

1981 ◽  
Vol 199 (3) ◽  
pp. 573-579 ◽  
Author(s):  
F M Dickinson ◽  
G J Hart ◽  
T M Kitson
Keyword(s):  
Ion Exchange ◽  
Aldehyde Dehydrogenase ◽  
Active Sites ◽  
Ion Exchange Chromatography ◽  
Exchange Chromatography ◽  
Ph Gradient ◽  
Original Activity ◽  
Covalent Interaction ◽  
Cytoplasmic Enzyme ◽  
Sheep Liver

1. Sheep liver cytoplasmic aldehyde dehydrogenase can be purified from contamination with the mitochondrial form of the enzyme by pH-gradient ion-exchange chromatography. The method is simple, reproducible and efficient. 2. The purified cytoplasmic enzyme retains about 2% of its original activity in the presence of a large excess of disulfiram. This suggests that the disulfiram-reactive thiol groups are not essential for covalent interaction with the aldehyde substrate during catalysis, as has sometimes been suggested. 3. Between 1.5 and 2.0 molecules of disulfiram per tetrameric enzyme molecule account for the observed loss of activity, suggesting that the enzyme may have only two functional active sites. 4. Experiments show that disulfiram-modified enzyme retains the ability to bind NAD+ and NADH.

scholarly journals Identification of a catalytically essential nucleophilic residue in sheep liver cytoplasmic aldehyde dehydrogenase

1991 ◽  
Vol 275 (1) ◽  
pp. 207-210 ◽  
Author(s):  
T M Kitson ◽  
J P Hill ◽  
G G Midwinter
Keyword(s):  
Aldehyde Dehydrogenase ◽  
Esterase Activity ◽  
Tryptic Digestion ◽  
Sheep Liver ◽  
Unequivocal Identification ◽  
Peptide Fractionation

Sheep liver cytoplasmic aldehyde dehydrogenase was labelled by reaction with the substrate p-nitrophenyl di[14C]methylcarbamate. After tryptic digestion and peptide fractionation the labelled residue was identified as Cys-302. This is the first unequivocal identification of the essential enzymic nucleophile in the esterase activity of aldehyde dehydrogenase. By implication, Cys-302 is probably also the residue that is acylated by aldehyde substrates and the first residue that is modified by disulfiram.

Chemical studies of high-Km aldehyde dehydrogenase from rat liver mitochondria

1991 ◽  
Vol 69 (2-3) ◽  
pp. 193-197 ◽  
Author(s):  
C. Stan Tsai ◽  
David J. Senior
Keyword(s):  
Dehydrogenase Activity ◽  
Rat Liver ◽  
Aldehyde Dehydrogenase ◽  
Esterase Activity ◽  
Liver Mitochondria ◽  
Rat Liver Mitochondria ◽  
Coenzyme Binding ◽  
High K ◽  
Chemical Studies ◽  
Ionizable Groups

Studies of pH-dependent kinetics implicate two ionizable groups in the dehydrogenase and esterase reactions catalysed by high-Km aldehyde dehydrogenase from rat liver mitochondria. Sensitized photooxidation completely arrests the bifunctional activities of the dehydrogenase. Carboxamidomethylation abolishes the dehydrogenase activity, whereas acetimidination eliminates the esterase activity. These results suggest that histidine (pKa near 6) and cysteine (pKa near 10) are likely the catalytic residues for the dehydrogenase activity, while the esterase activity is functionally related to histidine (pKa near 7) and a residue with the pKa value of 10–11. The two residues, a carboxyl group and an arginine, that discriminate between NAD+ and NADP+ are present at the coenzyme binding site of the mitochondrial high-Km aldehyde dehydrogenase from rat liver.Key words: aldehyde dehydrogenase, rat liver, mitochondria, esterase.

Inhibition of the dehydrogenase activity of sheep liver cytoplasmic aldehyde dehydrogenase by magnesium ions

Biochemistry ◽  
1983 ◽  
Vol 22 (4) ◽  
pp. 776-784 ◽  
Author(s):  
Adrian F. Bennett ◽  
Paul D. Buckley ◽  
Leonard F. Blackwell
Keyword(s):  
Dehydrogenase Activity ◽  
Aldehyde Dehydrogenase ◽  
Magnesium Ions ◽  
Sheep Liver
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