Cytochrome P-450 from Tulip Bulbs (Tulipa fosteriana L.) Oxidizes an Azo Dye Sudan I (1-Phenylazo-2-hydroxynaphthalene, Solvent Yellow 14) in vitro

1996 ◽  
Vol 61 (11) ◽  
pp. 1689-1696
Author(s):  
Marie Stiborová ◽  
Hana Hansíková
Keyword(s):  
Azo Dye ◽  
Microsomal Fraction ◽  
Point Of View ◽  
Transport Chain ◽  
Sudan I ◽  
Tulip Bulbs ◽  
Metabolism Of Xenobiotics ◽  
Cytochrome P 450

The microsomal fraction from tulip bulbs (Tulipa fosteriana L.) contains cytochrome P-450 enzymes catalyzing the NADPH-dependent oxidation of the xenobiotic substrate, an azo dye Sudan I (1-phenylazo-2-hydroxynaphthalene, Solvent Yellow 14). C-Hydroxy derivatives [1-(4-hydroxyphenylazo)-2-hydroxynaphthalene, 1-phenylazo-2,6-dihydroxynaphthalene, 1-(4-hydroxyphenylazo)-2,6-dihydroxynaphthalene] and the benzenediazonium ion are the products of the Sudan I oxidation. The oxidation of Sudan I has also been assessed in a reconstituted electron-transport chain with the isolated cytochrome P-450, isolated plant NADPH-cytochrome P-450 reductase and phospholipid. The results are discussed from the point of view of the role of cytochromes P-450 in the metabolism of xenobiotics in plants.

Alterations of Hepatic Microsomal Drug Metabolism by Glucagon

1975 ◽  
Vol 53 (5) ◽  
pp. 873-879 ◽  
Author(s):  
Jacob V. Aranda ◽  
Kenneth W. Renton
Keyword(s):  
Substrate Oxidation ◽  
Type I ◽  
Nadph Cytochrome ◽  
Transport Chain ◽  
Hexobarbital Sleeping Time ◽  
Nadph Oxidation ◽  
In Vivo Effects ◽  
Cytochrome P 450

The effect of glucagon on the components of the hepatic microsomal electron transport chain (NADPH oxidase, NADPH cytochrome c reductase (EC 1.6.2.4), cytochrome P-450, and NADPH cytochrome P-450 reductase), and on two representative oxidative pathways (aminopyrine N-demethylation, a type I substrate oxidation; and aniline p-hydroxylation, a type II substrate oxidation) was determined. Microsomes from rats pretreated with glucagon (300 μg/kg per day for 3 days) showed a significant decrease in NADPH oxidation and in aminopyrine N-demethylation with a prolonged hexobarbital sleeping time, and a significant increase in aniline p-hydroxylation. Microsomes from rats pretreated with a lower dose of glucagon (30 μg/kg per day for 3 days) showed a significant decrease in the microsomal N-demethylation of aminopyrine. Glucagon had no effect when added in vitro to microsomes, suggesting that the in vivo effects of glucagon are mediated indirectly in the intact animal.

Cytochrome P-450 and Peroxidase Oxidize Detoxication Products of Carcinogenic Aristolochic Acids (Aristolactams) to Reactive Metabolites Binding to DNA in vitro

1995 ◽  
Vol 60 (12) ◽  
pp. 2189-2199 ◽  
Author(s):  
Marie Stiborová ◽  
Eva Frei ◽  
Heinz H. Schmeiser ◽  
Manfred Wiessler
Keyword(s):  
Dna Adducts ◽  
Microsomal Cytochrome ◽  
Aristolochic Acids ◽  
Nuclease P1 ◽  
Order Of Magnitude ◽  
Prostaglandin H ◽  
Cytochrome P 450

We report the analysis of DNA adducts formed from aristolactams I and II, which are the final metabolites derived from carcinogenic aristolochic acids in vivo, after their oxidation by microsomal cytochrome P-450 and horseradish peroxidase in vitro. DNA adducts were detected and quantified using the nuclease P1-enhanced variation of the 32P-postlabeling assay. Quantitative analysis revelead that the extent of modification of DNA by aristolactams activated by peroxidase was more than one order of magnitude higher than for activation by microsomal cytochrome P-450. Peroxidase catalyzes the formation of active oxygen in the presence of NADH, H2O2 and aristolactams. Aristolactams are also oxidized by mammalian peroxidase prostaglandin H synthase. The possible role of aristolactams in carcinogenesis induced by aristolochic acid is discussed.

Plastoquinone-9 biosynthesis in cyanobacteria differs from that in plants and involves a novel 4-hydroxybenzoate solanesyltransferase

2012 ◽  
Vol 442 (3) ◽  
pp. 621-629 ◽  
Author(s):  
Radin Sadre ◽  
Christian Pfaff ◽  
Stephan Buchkremer
Keyword(s):  
Biosynthetic Pathway ◽  
In Vitro Assays ◽  
Transport Chain ◽  
In Vivo Labelling ◽  
Membrane Bound ◽  
Transformation Processes ◽  
Synechocystis Sp

PQ-9 (plastoquinone-9) has a central role in energy transformation processes in cyanobacteria by mediating electron transfer in both the photosynthetic as well as the respiratory electron transport chain. The present study provides evidence that the PQ-9 biosynthetic pathway in cyanobacteria differs substantially from that in plants. We identified 4-hydroxybenzoate as being the aromatic precursor for PQ-9 in Synechocystis sp. PCC6803, and in the present paper we report on the role of the membrane-bound 4-hydroxybenzoate solanesyltransferase, Slr0926, in PQ-9 biosynthesis and on the properties of the enzyme. The catalytic activity of Slr0926 was demonstrated by in vivo labelling experiments in Synechocystis sp., complementation studies in an Escherichia coli mutant with a defect in ubiquinone biosynthesis, and in vitro assays using the recombinant as well as the native enzyme. Although Slr0926 was highly specific for the prenyl acceptor substrate 4-hydroxybenzoate, it displayed a broad specificity with regard to the prenyl donor substrate and used not only solanesyl diphosphate, but also a number of shorter-chain prenyl diphosphates. In combination with in silico data, our results indicate that Slr0926 evolved from bacterial 4-hydroxybenzoate prenyltransferases catalysing prenylation in the course of ubiquinone biosynthesis.

scholarly journals The Role of the Cell Volume-Area Ratio in Thermodynamic Analysis of the Cancer Growth Control for In Vitro Experiments

2018 ◽  
Author(s):  
Umberto Lucia ◽  
Giulia Grisolia
Keyword(s):  
Growth Control ◽  
Area Ratio ◽  
Point Of View ◽  
Cancer Growth ◽  
Cyclic Process ◽  
Cell Life ◽  
Starting Point ◽  
Cell Changes

From a thermodynamic point of view, living cell life is no more than a cyclic process. It starts with the newly separated daughter cells and restarts when the next generations grow as free entities. In this cycle the cell changes its entropy. In cancer the growth control is damaged. In this paper we analyze the role of the volume-area ratio in cell in relation to the heat exchange between cell and its environment in order to point out the effect on the cancer growth. The result holds to a possible control of the cancer growth based on the heat exchanged by the cancer towards its environment, and the membrane potential variation, with the consequence of controlling the ions fluxes and the related biochemical reactions. This second law approach could represent a starting point for a possible future support for the anticancer therapies, in order to improve their effectiveness for the untreatable cancers.

Carcinogenic Non-Aminoazo Dye 1-Phenylazo-2-hydroxynaphthalene (Sudan I) Is Oxidized by Rat Liver Microsomal Cytochrome P-450 to Metabolites Binding to Macromolecules (Nucleic Acids and Proteins)

1992 ◽  
Vol 57 (7) ◽  
pp. 1537-1546 ◽  
Author(s):  
Marie Stiborová ◽  
Pavel Anzenbacher
Keyword(s):  
Nucleic Acids ◽  
Rat Liver ◽  
Chemical Carcinogenesis ◽  
Reactive Metabolites ◽  
Reactive Metabolite ◽  
Microsomal Cytochrome ◽  
Sudan I ◽  
Cytochrome P 450

Carcinogenic non-aminoazo dye 1-phenylazo-2-hydroxynaphthalene (Sudan I) is oxidized by microsomal cytochromes P-450 to reactive metabolite(s) binding to macromolecules (nucleic acids, proteins) in vitro. The extent of binding to macromolecules proceeded in the order: protein > rRNA > tRNA > DNA. The patern of products formed from Sudan I and binding of the reactive metabolites of this compound to macromolecules are dependent on the concentration of Sudan I, NADPH and on the duration of the incubation. The participation of the adducts formed with macromolecules in the initiation of chemical carcinogenesis is discussed.

scholarly journals Studies on the mechanism of hepatic microsomal N-oxide formation. The role of cytochrome P-450 and mixed-function amine oxidase in the N-oxidation of NN-dimethylaniline

1977 ◽  
Vol 164 (3) ◽  
pp. 487-496 ◽  
Author(s):  
P Hlavica ◽  
M Kehl
Keyword(s):  
Microsomal Fraction ◽  
Amine Oxidase ◽  
The Other ◽  
Rabbit Liver ◽  
Oxide Formation ◽  
Intact Rabbit ◽  
Liver Microsomal Fraction ◽  
Nadph Dehydrogenase ◽  
Cytochrome P 450

Evidence is established for the existence of alternative metabolic routes of N-oxidation of NN-dimethylaniline in rabbit liver microsomal fraction. One pathway involves the participation of two types of cytochrome P-450 with different sensitivities towards heat. Both types may represent distinct haemoprotein species or two physical forms of a single pigment. The other pathway is represented by the mixed-function amine oxidase. The enzyme lacks NADPH dehydrogenase activity and is insensitive to treatment with 2-bromo-4'-nitroacetophenone and steapsin: it catalyses N-oxidation of imipramine, trimethylamine and NN-dimethylaniline in molar proportions considerably different from those of the cytochrome P-450-supported reactions. Cytochrome P-450 is estimated to account for the formation of at least 50-60% of the total NN-dimethylaniline N-oxide formed in the intact rabbit liver microsomal fraction, the remainder arising from the action of the mixed-function amine oxidase.

scholarly journals The role of cytochrome P-450 in cholesterol biogenesis and catabolism

1972 ◽  
Vol 128 (2) ◽  
pp. 237-242 ◽  
Author(s):  
Sandra D. Atkin ◽  
Eileen D. Palmer ◽  
P. D. English ◽  
B. Morgan ◽  
M. A. Cawthorne ◽  
...  
Keyword(s):  
Cholesterol Metabolism ◽  
Carbon Disulphide ◽  
Normal Serum ◽  
Liver Cholesterol ◽  
Drug Metabolizing Enzyme ◽  
Metabolizing Enzyme ◽  
Cytochrome P 450

1. Adjuvant-induced arthritis in rats is accompanied by a loss of activity of the drug-metabolizing enzyme system and a decrease in hepatic cytochrome P-450. 2. Arthritic rats have normal serum and liver cholesterol concentrations. 3. The rate of biogenesis of cholesterol in vivo and in vitro from either [14C]acetate or [14C]mevalonate in arthritic rats was the same as or greater than that found in control rats. 4. Treatment of rats with carbon disulphide (1ml/kg) resulted in a loss of drug-metabolizing-enzyme activity and increased cholesterol biogenesis. 5. The activity of cholesterol 7α-hydroxylase in adjuvant-induced arthritic rats did not differ significantly from that in control rats. 6. Rats fed with cholestyramine had an elevated hepatic cholesterol 7α-hydroxylase activity, but neither the concentration of cytochrome P-450 nor the activity of the drug-hydroxylating enzyme, aminopyrine demethylase, was affected. 7. The relationships between drug hydroxylation and cholesterol metabolism are discussed.

scholarly journals A Proposal for new Quality attributes for Schedule R of the Indian Drugs and Cosmetics Act, 1940

2021 ◽  
Vol 9 (1) ◽  
pp. 10-14
Author(s):  
Bayya Subba Rao
Keyword(s):  
National Level ◽  
Good Health ◽  
Quality Attributes ◽  
Point Of View ◽  
Original Sin ◽  
Contraceptive Methods ◽  
Problem Solving Skills

Original sin is not life but it is a part of life.  It establishes psychological, mental and physical health.  Statistics reveal several deaths of pregnant mothers, ectopic pregnancy, child deaths or original sin related diseases, apart from lethal consequences which is out of the scope of this article. Use of contraceptive methods may be beneficial in several circumstances avoiding unwanted pregnancies. A few television channels were scrolling the various contraceptive methods and educating the citizens for a good health perspective.  The objective of this review is not only to enlighten the various contraceptive methods but also in knowing their failure level methods and some unique evaluation methods that can be included in Schedule R of the Drugs and Cosmetics Act, 1940 so as to append the quality attributes with in-vitro and in-vivo original sin correlated models.  The review illustrates role of researchers/pharmacist/medical professionals in problem solving skills and is also expected to answer the general questions experienced and witnessed by the author relating to original sin including gender sensitization.  In India, several national level bodies also insist for academic accreditations the contributions relating to gender sensitization and the article meets criteria as well.  If the author as a common man sends a sample for current products for assessing abstract attributes, does Central Drugs Laboratory can?, a thought in this direction is needed which in turn indicates role of questionnaires/instruments in the Drugs and Cosmetics Act, 1940 and Rules 1945.  Does a need of a statutory warning for original sin products is necessary, a question is raised and a review by persons skilled in art is proposed.  The article illustrates either side to the context.  The article also helps to overcome barriers from society, professional point of view relating to original sin related research either at the pre-clinical or at the clinical levels.

20-Hydroxyeicosatetraenoic acid is a potent dilator of mouse basilar artery: role of cyclooxygenase

2006 ◽  
Vol 291 (5) ◽  
pp. H2301-H2307 ◽  
Author(s):  
Xiang Fang ◽  
Frank M. Faraci ◽  
Terry L. Kaduce ◽  
Shawn Harmon ◽  
Mary L. Modrick ◽  
...  
Keyword(s):  
Basilar Artery ◽  
Brain Endothelial Cells ◽  
Epoxyeicosatrienoic Acid ◽  
Hydroxyeicosatetraenoic Acid ◽  
Mouse Brain Endothelial Cells ◽  
Endogenous Prostaglandins ◽  
Cytochrome P 450 ◽  
Dependent Mechanism

20-Hydroxyeicosatetraenoic acid (20-HETE), an arachidonic acid (AA) metabolite synthesized by cytochrome P-450 ω-oxidases, is reported to produce vasoconstriction in the cerebral circulation. However, we find that like 14,15-epoxyeicosatrienoic acid (14,15-EET), 20-HETE produces dilation of mouse basilar artery preconstricted with U-46619 in vitro. Indomethacin inhibited the vasodilation produced by 20-HETE but not by 14,15-EET, suggesting a cyclooxygenase (COX)-dependent mechanism. Metabolic studies indicated several mechanisms that may play a role in this process. Mouse brain endothelial cells (MBEC) converted 20-HETE to 20-OH-PGE2, which was as potent as PGE2 in dilating the basilar artery. 20-HETE also stimulated AA release and PGE2 and 6-keto-PGF1α production in MBEC. Furthermore, the basilar artery converted 20-HETE to 20-COOH-AA, which also produced COX-dependent dilation of the basilar artery. 20-COOH-AA increased AA release and PGE2 and 6-keto-PGF1α production by the MBEC, but to a lesser extent than 20-HETE. Whereas the conversion of 20-HETE to 20-OH-PGE2 and production of endogenous prostaglandins probably are primarily responsible for vasodilation, the production of 20-COOH-AA also may contribute to this process.

Hydrogen peroxide induces endothelium-dependent and -independent coronary arteriolar dilation: role of cyclooxygenase and potassium channels

2003 ◽  
Vol 285 (6) ◽  
pp. H2255-H2263 ◽  
Author(s):  
Naris Thengchaisri ◽  
Lih Kuo
Keyword(s):  
Hydrogen Peroxide ◽  
Smooth Muscle ◽  
Potassium Channels ◽  
Prostaglandin E ◽  
Inward Rectifier Potassium Channels ◽  
Cytochrome P 450 ◽  
Cox 1 ◽  
Coronary Arterioles

Hydrogen peroxide, a relatively stable reactive oxygen species, is known to elicit vasodilation, but its underlying mechanism remains elusive. Here, we examined the role of endothelial nitric oxide (NO), prostaglandin, cytochrome P-450-derived metabolites, and smooth muscle potassium channels in coronary arteriolar dilation to abluminal H2O2. Pig subepicardial coronary arterioles (50–100 μm) were isolated and pressurized without flow for in vitro study. Arterioles developed basal tone and dilated dose dependently to H2O2 (1–100 μM). Disruption of th endothelium and inhibition of cyclooxygenase (COX) by indomethacin produced identical attenuation of vasodilation to H2O2. Conversely, the vasodilation to H2O2 was not affected by either the NO synthase inhibitor NG-nitro-l-arginine methyl ester or the cytochrome P-450 enzyme blocker miconazole. Inhibition of the COX-1, but not the COX-2 pathway, attenuated H2O2-induced dilation similarly to indomethacin. The production of prostaglandin E2 (PGE2), but not prostaglandin I2, from coronary arterioles was significantly increased by H2O2. Furthermore, inhibition of PGE2 receptors with AH-6809 attenuated vasodilation to H2O2 similar to that produced by indomethacin. In the absence of a functional endothelium, H2O2-induced dilation was attenuated, in an identical manner, by a depolarizing agent KCl and a calcium-activated potassium (KCa) channel inhibitor iberiotoxin. However, PGE2-induced dilation was not affected by iberiotoxin. The endothelium-independent dilation to H2O2 was also insensitive to the inhibition of guanylyl cyclase, lipoxygenase, ATP-sensitive potassium channels, and inward rectifier potassium channels. These results suggest that H2O2 induces endothelium-dependent vasodilation through COX-1-mediated release of PGE2 and also directly relaxes smooth muscle by hyperpolarization through KCa channel activation.

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