scholarly journals Partial reversal of the acetaldehyde and butyraldehyde oxidation reactions catalysed by aldehyde dehydrogenases from sheep liver

1978 ◽  
Vol 175 (2) ◽  
pp. 753-756 ◽  
Author(s):  
G J Hart ◽  
F M Dickinson
Keyword(s):  
Acetic Anhydride ◽  
Mitochondrial Enzyme ◽  
Oxidation Reactions ◽  
Aldehyde Dehydrogenases ◽  
Cytoplasmic Enzyme ◽  
Sheep Liver ◽  
Michaelis Constants ◽  
Butyric Anhydride ◽  
Partial Reversal

In the presence of acetic anhydride or butyric anhydride, liver aldehyde dehydrogenases catalyse the oxidation of NADH at pH 7.0 and 25 degrees C. The maximum velocities and Michaelis constants for NADH at saturating anhydride concentrations are independent of which anhydride is used, the values being V′max. = 12 min-1 and Km for NADH = 9 micrometer for the mitochondrial enzyme and V′max = 25 min-1 and Km for NADH = 20 micrometer for the cytoplasmic enzyme. Substitution of [4A-2H]NADH for NADH resulted in 2-fold and 4-fold decreases in rate for the mitochondrial and cytoplasmic enzymes respectively.

scholarly journals The effect of some analogues of disulfiram on the aldehyde dehydrogenases of sheep liver

1976 ◽  
Vol 155 (2) ◽  
pp. 445-448 ◽  
Author(s):  
T M. Kitson
Keyword(s):  
Mitochondrial Enzyme ◽  
Aldehyde Dehydrogenases ◽  
Covalent Interaction ◽  
Cytoplasmic Enzyme ◽  
Sheep Liver ◽  
Structural Analogues

The effect of some close structural analogues of disulfiram on the activity of the cytoplasmic and mitochondrial aldehyde dehydrogenases of sheep liver was studied. Several thiuram disulphides are equally potent inhibitors of the cytoplasmic enzyme, but in all cases the mitochondrial enzyme is much less strongly affected. Tetramethylthiuram monosulphide decreases the activity of the cytoplasmic enzyme in a process apparently involving a covalent interaction.

scholarly journals The separation of sheep liver cytoplasmic and mitochondrial aldehyde dehydrogenases by isoelectric focusing, and observations on the purity of preparations of the cytoplasmic enzyme, and their sensitivity towards inhibition by disulfiram

1979 ◽  
Vol 179 (3) ◽  
pp. 709-712 ◽  
Author(s):  
F M Dickinson ◽  
S Berrieman
Keyword(s):  
Isoelectric Focusing ◽  
Aldehyde Dehydrogenase ◽  
Liver Enzymes ◽  
Mitochondrial Enzyme ◽  
Selective Precipitation ◽  
Aldehyde Dehydrogenases ◽  
Cytoplasmic Enzyme ◽  
Sheep Liver ◽  
Ph Range

Preparations of sheep liver cytoplasmic aldehyde dehydrogenase obtained by published methods were found by analytical isoelectric focusing in the pH range 5–8 to contain 5–10% by weight of the mitochondrial aldehyde dehydrogenase. Under the conditions used the pI of the cytoplasmic enzyme is 6.2 and that of the mitochondrial enzyme 6.6. The mitochondrial enzyme can be removed from the preparation by selective precipitation of the cytoplasmic enzyme with (NH4)2SO4. Kinetic experiments and inhibition experiments with disulfiram show that the properties of the two sheep liver enzymes are so different that the presence of 10% mitochondrial enzyme in preparations of the cytoplasmic enzyme can introduce serious errors into results. Our results suggest that the presence of 10 microM-disulfiram in assays may completely inactivate the pure cytoplasmic enzyme. This result is in contrast with a previous report [kitson (1978) Biochem. U. 175, 83–90].

scholarly journals Reaction between sheep liver mitochondrial aldehyde dehydrogenase and various thiol-modifying reagents

1989 ◽  
Vol 261 (1) ◽  
pp. 281-284 ◽  
Author(s):  
K M Loomes ◽  
T M Kitson
Keyword(s):  
Aldehyde Dehydrogenase ◽  
Related Compound ◽  
Physiological Responses ◽  
Enzymic Activity ◽  
Cysteine Residues ◽  
Mitochondrial Enzyme ◽  
Step Process ◽  
Cytoplasmic Enzyme ◽  
Sheep Liver

Sheep liver mitochondrial aldehyde dehydrogenase reacts with 2,2′-dithiodipyridine and 4,4′-dithiodipyridine in a two-step process: an initial rapid labelling reaction is followed by slow displacement of the thiopyridone moiety. With the 4,4′-isomer the first step results in an activated form of the enzyme, which then loses activity simultaneously with loss of the label (as has been shown to occur with the cytoplasmic enzyme). With 2,2′-dithiodipyridine, however, neither of the two steps of the reaction has any effect on the enzymic activity, showing that the mitochondrial enzyme possesses two cysteine residues that must be more accessible or reactive (to this reagent at least) than the postulated catalytically essential residue. The symmetrical reagent 5,5′-dithiobis-(1-methyltetrazole) activates mitochondrial aldehyde dehydrogenase approximately 4-fold, whereas the smaller related compound methyl l-methyltetrazol-5-yl disulphide is a potent inactivator. These results support the involvement of mixed methyl disulphides in causing unpleasant physiological responses to ethanol after the ingestion of certain antibiotics.

scholarly journals The effect of disulfiram on the aldehyde dehydrogenases of sheep liver

1975 ◽  
Vol 151 (2) ◽  
pp. 407-412 ◽  
Author(s):  
T M Kitson
Keyword(s):  
Ph Dependence ◽  
Maximum Velocity ◽  
Enzyme Reaction ◽  
Thiol Group ◽  
Inhibitory Effect ◽  
Mitochondrial Enzyme ◽  
Aldehyde Dehydrogenases ◽  
Sheep Liver ◽  
Rate Profile

1. The effect of disulfiram on the activity of the cytoplasmic and mitochondrial aldehyde dehydrogenases of sheep liver was studied. 2. Disulfiram causes an immediate inhibition of the enzyme reaction. The effect on the cytoplasmic enzyme is much greater than on the mitochondrial enzyme. 3. In both cases, the initial partial inhibition is followed by a gradual irreversible loss of activity. 4. The pH-rate profile of the inactivation of the mitochondrial enzyme by disulfiram and the pH-dependence of the maximum velocity of the enzyme-catalysed reaction are both consistent with the involvement of a thiol group. 5. Excess of 2-mercaptoethanol or GSH abolishes the effect of disulfiram. However, equimolar amounts of either of these reagents and disulfiram cause an effect greater than does disulfiram alone. It was shown that the mixed disulphide, Et2N-CS-SS-CH2-CH2OH, strongly inhibits aldehyde dehydrogenase. 6. The inhibitory effect of diethyldithiocarbamate in vitro is due mainly to contamination by disulfiram.

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.

A genetic analysis of the alpha-glycerophosphate oxidase locus in Drosophila melanogaster.

Genetics ◽  
1988 ◽  
Vol 120 (3) ◽  
pp. 755-766
Author(s):  
M B Davis ◽  
R J MacIntyre
Keyword(s):  
Drosophila Melanogaster ◽  
Genetic Analysis ◽  
Structural Gene ◽  
Mitochondrial Enzyme ◽  
Synthetic Lethal ◽  
Lethal Phenotype ◽  
Cytoplasmic Enzyme ◽  
Glycerophosphate Dehydrogenase ◽  
Null Mutants

Abstract The gene for alpha-glycerophosphate oxidase, the nuclear encoded mitochondrial enzyme of the alpha-glycerophosphate cycle (alpha GP); has been mapped in Drosophila melanogaster. Several interstitial deficiencies in region 50c-53AB of chromosome 2R were used to localize the structural gene to 52D2-5. In addition, mutations of alpha GPO were generated; alpha GPO mutants are viable yet flightless. Interactions of alpha GPO with alpha-glycerophosphate dehydrogenase (alpha GPDH), the cytoplasmic enzyme of the alpha GP cycle, were investigated through the synthesis of a series of alpha GPDHnull-alpha GPOnull double mutants. Of the six double null mutants constructed, four alpha GPDH-alpha GPO double nulls are viable and flightless. Two double mutants, however, exhibit an allelic-dependent synthetic lethal phenotype.

scholarly journals The removal of cytosolic-type aldehyde dehydrogenase from preparations of sheep liver mitochondrial aldehyde dehydrogenase and the unusual properties of the purified mitochondrial enzyme in assays

1984 ◽  
Vol 224 (1) ◽  
pp. 163-169
Author(s):  
S Allanson ◽  
F M Dickinson
Keyword(s):  
Aldehyde Dehydrogenase ◽  
The Other ◽  
Ph Gradient ◽  
Mitochondrial Enzyme ◽  
Sheep Liver ◽  
Species Being ◽  
Gradient Chromatography ◽  
Lag Phases

The pI approximately 5.2 isoenzymes of mitochondrial aldehyde dehydrogenase were separated from the other isoenzymes by pH-gradient chromatography on DEAE-Sephacel. The pI approximately 5.2 material is immunologically identical with cytosolic aldehyde dehydrogenase. It also shows sensitivity to 20 microM-disulfiram and insensitivity to 4M-urea in assays. These and other criteria seem to establish that the material is identical with the cytosolic enzyme. Mitochondrial enzyme that had been purified to remove pI approximately 5.2 isoenzymes shows concentration-dependent lag phases in assays. These effects are possibly due to the slow establishment of equilibrium between tetramer and either dimers or monomers, with the dissociated species being intrinsically more active than the tetramer.

scholarly journals HTS1 encodes both the cytoplasmic and mitochondrial histidyl-tRNA synthetase of Saccharomyces cerevisiae: mutations alter the specificity of compartmentation.

Genetics ◽  
1992 ◽  
Vol 132 (4) ◽  
pp. 987-1001 ◽  
Author(s):  
M I Chiu ◽  
T L Mason ◽  
G R Fink
Keyword(s):  
Mitochondrial Function ◽  
Nuclear Gene ◽  
Trna Synthetase ◽  
Mitochondrial Enzyme ◽  
Trna Synthetases ◽  
Cytoplasmic Enzyme ◽  
Amino Terminal ◽  
Lacz Fusions ◽  
Targeting Signal ◽  
Amino Terminal Sequence

Abstract Genetic and biochemical evidence shows that a single nuclear gene HTS1 encodes both the mitochondrial and cytoplasmic histidyl-tRNA synthetases (Hts). The gene specifies two messages, one with two in-frame ATGs (-60 and +1) and another with only the downstream ATG (+1). We have made a new set of mutations that enables us to express only the mitochondrial or the cytoplasmic form and compared the subcellular distribution of the Hts1 protein in these mutants and wild type, using an antibody that interacts with both the mitochondrial and cytoplasmic Hts1 as well as Hts1::LacZ fusions. Mutations in the upstream ATG (-60) or frameshift mutations in the presequence affect only the mitochondrial enzyme and not the cytoplasmic enzyme. Mutations in the downstream ATG (+1 ATG to ATC) destroy the function of the cytosolic enzyme, but do not affect the function of the mitochondrial enzyme. Overexpression of this construct restores cytoplasmic function. Cells expressing a truncated form of Hts containing a deletion of the first 20 amino-terminal residues (Htsc) produce a functional cytoplasmic enzyme, which does not provide mitochondrial function. Overexpression of this truncated cytoplasmic protein provides mitochondrial function and produces detectable levels of the synthetase in the mitochondrion. These experiments suggest that Hts1 contains two domains that together allow efficient localization of Htsm to the mitochondrion: an amino-terminal presequence in the mitochondrial precursor that is likely cleaved upon delivery to the mitochondrion and a second amino-terminal sequence (residues 21-53) present in both the precursor and the cytoplasmic form. Neither one by itself is sufficient to act as an efficient mitochondrial targeting signal. Using our antibody we have been able to detect a protein of increased molecular mass that corresponds to that of the predicted precursor. Taken together these studies show that the specificity of compartmentation of the Hts protein depends upon both the primary sequence and the concentration of the protein in the cell.

Notizen: Coenzyme Binding at Different Ionization States of Cytoplasmic and Mitochondrial Malate Dehydrogenase

1982 ◽  
Vol 37 (5-6) ◽  
pp. 547-549 ◽  
Author(s):  
Klaus Schwerdtfeger ◽  
Christoph Woenckhaus ◽  
David M. Parker ◽  
John J. Holbrook
Keyword(s):  
Binding Site ◽  
Malate Dehydrogenase ◽  
Lower Limit ◽  
Mitochondrial Enzyme ◽  
Binding Studies ◽  
Active Centre ◽  
Cytoplasmic Enzyme ◽  
Coenzyme Binding ◽  
Mitochondrial Malate Dehydrogenase ◽  
Ionizable Groups

Abstract pH-titrations with NADH show two ionizable groups in mitochondrial and cytoplasmic malate dehydrogenase, the first with a pKa in the range 6.8 -8.3 for the mitochondrial and 6.4-7.8 for the cytoplasmic enzyme, the second with a lower limit at 10.2 resp. 11. Comparison with bis-(dihydronicotinamide)-dinucleotide and dihydronicotina-mide-ribosyl-P2-ribose-pyrophosphate instead of NADH indicates that the second alkaline ionization is caused by a residue placed near the adenine binding site of the active centre of the two isoenzymes. Binding studies with NADH and NAD+ give evidence for the participation of a group in the mitochondrial enzyme with pKa 6.8, deprotonation of which is necessary for detectable association of NAD+. In contrast the fixation of NAD+ to the cytoplasmic enzyme is independent of pH.

scholarly journals Production of Butyric Anhydride Using Single Reactive Distillation Column with Internal Material Circulation

Processes ◽  
2019 ◽  
Vol 8 (1) ◽  
pp. 1 ◽  
Author(s):  
Guanghui Chen ◽  
Fushuang Jin ◽  
Xiaokai Guo ◽  
Shuguang Xiang ◽  
Shaohui Tao
Keyword(s):  
Acetic Anhydride ◽  
Butyric Acid ◽  
Distillation Column ◽  
Reactive Distillation ◽  
Reaction System ◽  
Total Annual Cost ◽  
Material Circulation ◽  
Butyric Anhydride ◽  
Better Than ◽  
Column Process

The traditional two-column reactive distillation (RD) process is used for the production of butyric anhydride, which is synthesized with butyric acid and acetic anhydride via a reversible reaction. In this work, a novel process with a single RD column (SRDC) is designed for the production of butyric anhydride, where the second distillation column for separating excess reactant is removed based on the boiling point profile of the reaction system. Two applications of the proposed SRDC process, namely SRDC with excess butyric acid or acetic anhydride circulating internally, are economically optimized, and the results show that both SRDC processes have a lower total annual cost (TAC) than the traditional two-column process. Furthermore, from the perspective of TAC, the application with an excess feed of butyric acid is better than the application with excess acetic anhydride. The developed technique may also be applied to retrofit other traditional two-column RD processes, where the overhead and bottom products are the lightest and heaviest components of the reaction system, respectively, and no azeotrope is involved in the RD column.

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