scholarly journals Investigation of the arylnitroso reductase activity of pig liver aldehyde reductase

1986 ◽  
Vol 235 (2) ◽  
pp. 537-543 ◽  
Author(s):  
J Kovář ◽  
J Plocek
Keyword(s):  
Reductase Activity ◽  
Alcohol Oxidation ◽  
Aldehyde Reductase ◽  
Reaction Sequence ◽  
Pig Liver ◽  
Kinetics Of

The reduction of p-nitroso-N-dimethylaniline, p-nitroso-N-diethylaniline, p-nitrosophenol and p-nitroso-N-phenylaniline with NADPH in the presence of aldehyde reductases 1 and 2 is described. The reactivity of these nitroso substrates is increased by hydrophobic substituents and those promoting OH- elimination from the molecule of the reduced substrate. NN-Dimethylbenzoquinonedi-iminium cation was proved to be the reaction product formed from p-nitroso-N-dimethylaniline. The kinetics of the reduction of p-nitroso-N-dimethylaniline catalysed with aldehyde reductase 1 are rather complex at pH 7, and the preferred-pathway mechanism is probably involved. The reaction sequence approaches the ordered pattern at pH 8.5. It was shown that NADPH in equilibrium NADP+ recyclization proceeds in the presence of NADP+, p-nitroso-N-dimethylaniline, cyclohexanol and aldehyde reductase 1, the alcohol oxidation being the slowest step in this reaction. However, the rate of cyclohexanol oxidation surpasses that of the dissociation of NADPH from the enzyme.

scholarly journals Kinetic studies of the mechanism of pig kidney aldehyde reductase

1981 ◽  
Vol 193 (2) ◽  
pp. 485-492 ◽  
Author(s):  
F F Morpeth ◽  
F M Dickinson
Keyword(s):  
Initial Rate ◽  
Kinetic Studies ◽  
Random Order ◽  
Alcohol Oxidation ◽  
Aldehyde Reductase ◽  
Pig Kidney ◽  
Binary Complexes ◽  
Inhibition Studies ◽  
Kinetics Of ◽  
Aldehyde Reduction

Initial-rate measurements were made of the oxidations of pyridine-3-methanol and glycerol by NADP+ and of the reduction of the corresponding aldehydes by NADPH catalysed by pig kidney aldehyde reductase. In addition, a brief survey of the specificity of the enzyme towards aldehyde substrates and its sensitivity to the inhibitors ethacrynic acid, sodium barbitone and warfarin was made. The detailed kinetic work indicates a compulsory mechanism for aldehyde reduction, with NADPH binding before aldehyde. For alcohol oxidation, however, it is necessary to postulate the formation of kinetically significant amounts of binary complexes of the type enzyme-alcohol to explain the results. Thus, for alcohol oxidation random-order addition of substrates may occur. Inhibition studies of the kinetics of aldehyde reduction in the presence of the corresponding alcohol product provide further evidence for the existence of enzyme-alcohol complexes. Finally, detailed kinetic studies were made of the inhibition of pyridine-3-aldehyde reduction by sodium barbitone. The mechanism of the inhibition is discussed.

scholarly journals Aldehyde reductase is a major protein associated with 3-deoxyglucosone reductase activity in rat, pig and human livers

1991 ◽  
Vol 279 (3) ◽  
pp. 903-906 ◽  
Author(s):  
T Kanazu ◽  
M Shinoda ◽  
T Nakayama ◽  
Y Deyashiki ◽  
A Hara ◽  
...  
Keyword(s):  
Rat Liver ◽  
Reductase Activity ◽  
Catalytic Efficiency ◽  
Major Protein ◽  
Aldehyde Reductase ◽  
Reductase Inhibitors ◽  
Major Species ◽  
Human Livers

3-Deoxyglucosone reductase activity in the extracts of rat, pig and human livers was potently inhibited by aldehyde reductase inhibitors. The major species of 3-deoxyglucosone reductase purified from human and pig livers were biochemically and immunochemically identical with aldehyde reductase. The two enzymes and rat liver aldehyde reductase exhibited higher catalytic efficiency for 3-deoxyglucosone than for D-glucuronate, a representative substrate of aldehyde reductase.

Aldehyde reductase activity in the antennae ofHelicoverpa armigera

2014 ◽  
pp. n/a-n/a ◽  
Author(s):  
H. Guo ◽  
A. Del Corso ◽  
L-Q. Huang ◽  
U. Mura ◽  
P. Pelosi ◽  
...  
Keyword(s):  
Reductase Activity ◽  
Aldehyde Reductase

scholarly journals The kinetic mechanism of the major form of ox kidney aldehyde reductase with d-glucuronic acid

1982 ◽  
Vol 205 (2) ◽  
pp. 381-388 ◽  
Author(s):  
Ann K. Daly ◽  
Timothy J. Mantle
Keyword(s):  
Glucuronic Acid ◽  
Alternative Pathway ◽  
Kinetic Mechanism ◽  
Product Inhibition ◽  
Aldehyde Reductase ◽  
Major Form ◽  
Mechanism Of Inhibition ◽  
Steady State Kinetics ◽  
Inhibition Studies ◽  
Kinetics Of

The steady-state kinetics of the major form of ox kidney aldehyde reductase with d-glucuronic acid have been determined at pH7. Initial rate and product inhibition studies performed in both directions are consistent with a Di-Iso Ordered Bi Bi mechanism. The mechanism of inhibition by sodium valproate and benzoic acid is shown to involve flux through an alternative pathway.

Pcal_1311, an alcohol dehydrogenase homologue from Pyrobaculum calidifontis, displays NADH-dependent high aldehyde reductase activity

Extremophiles ◽  
2017 ◽  
Vol 21 (6) ◽  
pp. 1101-1110 ◽  
Author(s):  
Raza Ashraf ◽  
Naeem Rashid ◽  
Tamotsu Kanai ◽  
Tadayuki Imanaka ◽  
Muhammad Akhtar
Keyword(s):  
Alcohol Dehydrogenase ◽  
Reductase Activity ◽  
Aldehyde Reductase ◽  
Pyrobaculum Calidifontis

A549 subclones demonstrate heterogeneity in toxicological sensitivity and antioxidant profile

2002 ◽  
Vol 283 (4) ◽  
pp. L726-L736 ◽  
Author(s):  
Nobuo Watanabe ◽  
Dale A. Dickinson ◽  
David M. Krzywanski ◽  
Karen E. Iles ◽  
Hongqiao Zhang ◽  
...  
Keyword(s):  
Actinomycin D ◽  
Reductase Activity ◽  
A549 Cells ◽  
Aldehyde Reductase ◽  
Mechanistic Studies ◽  
Caspase Activation ◽  
Protein Synthesis Inhibitors ◽  
Antioxidant Profile ◽  
Glutathione Reductase Activity ◽  
Limiting Dilution

In A549 cell culture, significant variability was found in sensitivity to actinomycin D. Using limiting dilution, actinomycin D-susceptible (G4S) and -resistant (D3R) subclones were isolated. G4S cells were also susceptible to protein synthesis inhibitors, a redox cycling quinone, and an electrophile with concomitant activation of caspases 3 and 9. D3R cells were resistant to these agents without caspase activation. Antioxidant profiles revealed that D3R cells had significantly higher glutathione and glutathione reductase activity but markedly lower catalase, glutathione peroxidase, and aldehyde reductase activities than G4S cells. Thus A549 cells contain at least two distinct subpopulations with respect to predisposition to cell death and antioxidant profile. Because sensitivities to agents and the antioxidant profile were inconsistent, mechanisms independent of antioxidants, including the apparent inability to activate caspases in D3R cells, may play an important role. Regardless, the results suggest that antioxidant profiles of asymmetrical cell populations cannot predict sensitivity to oxidants and warn that the use of single subclones is advisable for mechanistic studies using A549 or other unstable cell lines.

STUDIES ON CORTICOSTERONE C-20 REDUCTION IN THE MOUSE

1962 ◽  
Vol 40 (1) ◽  
pp. 1797-1810 ◽  
Author(s):  
R. E. Krehbiel ◽  
A. F. Burton ◽  
Marvin Darrach
Keyword(s):  
Intravenous Injection ◽  
Mouse Liver ◽  
Enzyme Preparation ◽  
Soluble Fraction ◽  
Reductase Activity ◽  
Kinetics Of

The intravenous injection of corticosterone in the mouse was followed by liver assays for corticosterone and 20α- and 20β-dihydrocorticosterone. The 20α-epimer proved to be the more abundant product. Corticosterone 20α-reductase activity of mouse liver was shown to be associated with the dialyzed soluble fraction of the cell which served as an enzyme preparation for a study of certain properties of corticosterone 20α-reductase and the kinetics of the forward and reverse reactions.

Studies on Partially Purified Pig Liver Steroid Δ4-5β-Reductase Activity

1973 ◽  
Vol 51 (12) ◽  
pp. 1661-1668 ◽  
Author(s):  
Edward J. Van Doorn ◽  
John C. Nduaguba ◽  
Albert F. Clark
Keyword(s):  
Molecular Weight ◽  
Enzyme Activity ◽  
Enzyme Preparation ◽  
Reductase Activity ◽  
Enzymatic Reaction ◽  
Ph Optimum ◽  
Pig Liver ◽  
Liver Cytosol ◽  
End Products ◽  
Tris Maleate

Some properties of partially purified steroid Δ4-5β-reductase activity of pig liver cytosol have been studied using testosterone as substrate. The enzymatic activity was stable for 72 h at 4° when stored in 0.05 M Tris–maleate buffer, pH 7.4 or 8.4; storage at pH 8 at 4° resulted in a 25% decrease in activity in 30 days. The pH optimum in Tris–maleate buffers was 6.4. Enzyme activity was completely inhibited by 0.2 mM p-chloromercuribenzenesulfonate and 0.2 mM p-chloromercuribenzoate. Enzyme activity was reduced by 20% and 45% with 1.0 mM iodoacetamide and 1.0 mM N-ethylmaleimide, respectively. The end products of the enzymatic reaction, NADP+ and 5β-dihydrotestosterone, inhibited the rate of reduction of testosterone. Testosterone Δ4-5β-reductase activity was present in protein of molecular weight 25 000–30 000, as determined by gel filtration.The enzyme preparation reduced a variety of C19 and C21 steroids. The highest activity (twice that for testosterone) was found with aldosterone as substrate.

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