Organic solvents as modifiers of aldrin epoxidase in reconstituted monooxygenase systems and in microsomes.

@article{Wolff1989OrganicSA,
  title={Organic solvents as modifiers of aldrin epoxidase in reconstituted monooxygenase systems and in microsomes.},
  author={Thomas Wolff and H Wanders and F. Peter Guengerich},
  journal={Biochemical pharmacology},
  year={1989},
  volume={38 23},
  pages={
          4217-23
        }
}
To examine the response of individual cytochrome P-450 species catalysing the epoxidation of aldrin (Wolff T and Guengerich FP, Biochem Pharmacol 36: 2581-2588, 1987), monooxygenase systems reconstituted from these species were assayed in the presence of 5% (v/v) = 0.87 M ethanol. The activity of cytochromes P-450PB-B and P-450PB-D, two enzymes inducible by phenobarbital was increased seven-fold. The activity of two other P-450 enzymes purified from these animals was either inhibited by 50%, as… 
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References

SHOWING 1-10 OF 33 REFERENCES
Aldrin epoxidation, a highly sensitive indicator specific for cytochrome P-450-dependent mono-oxygenase activities.
TLDR
The results demonstrate that aldrin epoxidation offers a selective and sensitive assay for the activity of mono-oxygenases dependent on cytochrome P-450 forms and suggest that the same or (a) similar form(s) of mono -oxygenase catalyze the ep oxidation in the three different microsomal preparations.
Aldrin epoxidation catalyzed by purified rat-liver cytochromes P-450 and P-448. High selectivity for cytochrome P-450.
Aldrin epoxidation was studied in monooxygenase systems reconstituted from purified rat liver microsomal cytochrome P-450 or P-448, NADPH-cytochrome c reductase, dilauroylphosphatidylcholine and
Identification of the cyanopregnenolone-inducible form of hepatic cytochrome P-450 as a catalyst of aldrin epoxidation.
TLDR
P-450PCN, P-450PB, and probably other cytochromes P- 450 catalyze aldrin epoxidation, precluding use of this enzyme as a specific marker of a single form of the cytochrome.
Differences in the biochemical properties of aldrin epoxidase, a cytochrome P-450-dependent monooxygenase, in various tissues.
TLDR
It is confirmed that more than one form of cytochrome P-450 supports aldrin epoxidase in the liver, but it may be a different type, or regulated in a different manner in these tissues.
Rat liver cytochrome P-450 isozymes as catalysts of aldrin epoxidation in reconstituted monooxygenase systems and microsomes.
TLDR
The results reveal that aldrin epoxidation is a reaction indicative of male specific and of phenobarbital-inducible cytochrome P-450 isozymes in rat liver.
Interaction of liver microsomal cytochrome P-450 and NADPH-cytochrome P-450 reductase in the presence and absence of lipid.
TLDR
The results lead to the conclusion that the major effect of phospholipids in P-450-based enzyme systems is the facilitation of an active P- 450:NADPH-P-450 reductase complex.
Lack of relationship between debrisoquine 4-hydroxylation and other cytochrome P-450 dependent reactions in rat and human liver.
TLDR
The results indicate that DQH in the rat and in man reflects the activity of a cytochrome P-450 species not related to various other known cyto Chrome P- 450 functions.
Characterization of three highly purified cytochromes P-450 from hepatic microsomes of adult male rats.
TLDR
Results of this study indicate that rat hepatic microsomal cytochromes P-450 are composed of at least four hemoproteins with CO-reduced absorbance maxima between 447-448 nm and a minimum of four microsomes are now known to 16 alpha-hydroxylate testosterone.
Relationship between oxidative metabolism of 2-acetylaminofluorene, debrisoquine, bufuralol, and aldrin in human liver microsomes.
TLDR
It is concluded, based on these multiple cross-correlations, that common cytochrome P-450 isoenzymes are involved in the formation of AAF metabolites, while the metabolism of debrisoquine, bufuralol, and aldrin is unrelated to the metabolic of this carcinogen in human liver microsomes.
Roles of cytochrome P-450 enzymes in chemical carcinogenesis and cancer chemotherapy.
Studies involving the metabolism of chemical carcinogens were important in the discovery and initial characterization of the cytochrome P-450 enzyme system. The Millers and their associates
...
1
2
3
4
...