Purified fusion enzyme between rat cytochrome P4501A1 and yeast NADPH-cytochrome P450 oxidoreductase. (1/68)

A genetically engineered fusion enzyme between rat P4501A1 and yeast P450 reductase in the microsomal fraction of the recombinant yeast AH22/pAFCR1 was purified. The purified enzyme showed a typical CO-difference spectrum of P4501A1 and a single band with an apparent molecular weight of 125,000 on sodium dodecyl sulfate polyacrylamide gel electrophoresis. This agreed with the molecular weight of 131,202 calculated from the amino acid sequence. The purified enzyme showed both 7-ethoxycoumarin o-deethylase activity and horse heart cytochrome c reductase activity in the presence of NADPH. The 7-ethoxycoumarin o-deethylase activity depended on the species of lipid used for the reconstitution of the purified fusion enzyme although the purified enzyme showed the activity without reconstitution. The purified fusion enzyme had the Km value of 26 microM for 7-ethoxycoumarin and the maximal turnover rate of 29 mol product/min/mol enzyme at 30 degrees C.  (+info)

Engineering and biochemical characterization of the rat microsomal cytochrome P4501A1 fused to ferredoxin and ferredoxin-NADP(+) reductase from plant chloroplasts. (2/68)

Fusion proteins of rat cytochrome P4501A1 with maize ferredoxin I (Fd) and pea ferredoxin NADP(+) reductase (FNR), the last electron transfer proteins of the photosynthetic channel in plant chloroplasts, were obtained by gene fusion in the yeast expression vector pAAH5N. The encoded fusion proteins P4501A1-Fd, P4501A1-FNR, P4501A1-Fd-FNR and P4501A1-FNR-Fd were produced in microsomes of the yeast Saccharomyces cerevisiae AH22. Enzymatic assays were carried out in vitro with the isolated microsomes. P4501A1-Fd-FNR and P4501A1-FNR-Fd were found to catalyze P450-monooxygenase activities towards 7-ethoxycoumarin and the herbicide chlortoluron. P4501A1-Fd-FNR was the most efficient enzyme as measured in vitro in ferricyanide and cytochrome c reductions, as well as P450-monooxygenase assays. Apparent K(m) and k(cat) of P4501A1-Fd-FNR were 70 microM and 7800 min(-1) for NADPH, 13.2 microM and 51.1 min(-1) for 7-ethoxycoumarin, and 21.3 microM and 23. 8 min(-1) for the herbicide chlortoluron, respectively. Fd in P4501A1-Fd-FNR fusion enzyme was found to be a limiting factor compared to P4501A1 fused to the yeast NADPH-cytochrome P450 reductase, an artificial enzyme described previously. The efficiency of electron transfer in the P4501A1 fusion proteins and a possible in vivo molecular coupling of Fd and FNR with microsomal cytochrome P4501A1 produced in plant chloroplasts are discussed.  (+info)

Inhibitory effects of 1,4-naphthoquinone derivatives on rat cytochrome P4501A1-dependent monooxygenase activity in recombinant yeast microsomes. (3/68)

We reported previously that various naphthoquinone derivatives inhibited cytochrome P450-dependent monooxygenase of liver and placenta microsomes [Muto, N. et al. (1987) Biochem. Biophys. Res. Commun. 146, 487-494]. To understand the complex inhibitory behaviors that were observed, it is desirable to study the relationship between structure and inhibitory activity of naphthoquinones in a simplified system containing a single P450 species. In the present study, the inhibitory effects of six derivatives of 1,4-naphthoquinone (hereafter referred to as NQ) on rat cytochrome P4501A1-dependent 7-ethoxycoumarin O-deethylation were examined using yeast microsomes containing overexpressed rat P4501A1. Of these, 2-methyl-5-hydroxy-NQ, 2-methyl-NQ, 2-hydroxy-NQ, and NQ showed competitive inhibition, whereas 5,8-dihydroxy-NQ and 5-hydroxy-NQ showed noncompetitive inhibition. Judging from the inhibitor constant (K(i)), the binding affinity of the four competitive inhibitors for the substrate-binding pocket of P4501A1 is in the order: 2-CH(3)-5-OH-NQ > 2-CH(3)-NQ > NQ >> 2-OH-NQ. On binding with P4501A1, 2-CH(3)-5-OH-NQ, 2-CH(3)-NQ, and NQ induced distinct Type II, Type I, and reverse Type I spectra, respectively. These results indicate that methyl and hydroxyl groups introduced into NQ have unique effects on their binding mode and binding affinity.  (+info)

Biphasic kinetic behavior of rat cytochrome P-4501A1-dependent monooxygenation in recombinant yeast microsomes. (4/68)

Rat cytochrome P-4501A1-dependent monooxygenase activities were examined in detail using recombinant yeast microsomes containing rat cytochrome P-4501A1 and yeast NADPH-P-450 reductase. On 7-ethoxycoumarin, which is one of the most popular substrates of P-4501A1, the relationship between the initial velocity (v) and the substrate concentration ([S]) exhibited non-linear Michaelis-Menten kinetics. Hanes-Woolf plots ([S]/v vs. [S]) clearly showed a biphasic kinetic behavior. Aminopyrine N-demethylation also showed a biphasic kinetics. The regression analyses on the basis of the two-substrate binding model proposed by Korzekwa et al. (Biochemistry 37 (1998) 4137-4147) strongly suggest the presence of the two substrate-binding sites in P-4501A1 molecules for those substrates. An Arrhenius plot with high 7-ethoxycoumarin concentration showed a breakpoint at around 28 degrees C probably due to the change of the rate-limiting step of P-4501A1-dependent 7-ethoxycoumarin O-deethylation. However, the addition of 30% glycerol to the reaction mixture prevented observation of the breakpoint. The methanol used as a solvent of 7-ethoxycoumarin was found to be a non-competitive inhibitor. Based on the inhibition kinetics, the real V(max) value in the absence of methanol was calculated. These results strongly suggest that the recombinant yeast microsomal membrane containing a single P-450 isoform and yeast NADPH-P-450 reductase is quite useful for kinetic studies on P-450-dependent monooxygenation including an exact evaluation of inhibitory effects of organic solvents.  (+info)

Maturational changes in CYP2D16 expression and xenobiotic metabolism in adrenal glands from male and female guinea pigs. (5/68)

CYP2D16 is expressed at high levels in the zona reticularis (ZR) of guinea pig adrenal glands and contributes to adrenal metabolism of xenobiotics. Studies were done to evaluate the effects of age and gender on adrenal CYP2D16 expression and xenobiotic metabolism. In both male and female guinea pigs at 1, 7, 14, or 30 weeks of age, in situ hybridization and immunohistochemistry confirmed that CYP2D16 was highly localized to the ZR of the adrenal gland. The steroidogenic P450 isozyme, CYP17, by contrast, was expressed in both the zona fasciculata and ZR. The intensity of CYP2D16 staining was not age- or gender-dependent. However, the proportion of each adrenal gland comprised by ZR and thus expressing CYP2D16 increased with aging in both sexes and was greater in males than in females. The rates of metabolism of bufuralol, a CYP2D-selective substrate, by adrenal microsomal preparations generally correlated with the amount of ZR (and CYP2D16) in the gland. Thus, adrenal xenobiotic-metabolizing activities were greater in males than in females at all ages and increased with aging in males. However, the rates of bufuralol metabolism declined in sexually mature females (14 weeks) from the levels found in prepubertal females (7 weeks) and then increased markedly in retired breeders (30 weeks), suggesting an inhibitory effect of estrogens on enzyme activity. The results indicate that the age and gender differences in adrenal CYP2D16 content are largely determined by differences in the size of the ZR rather than the concentrations of CYP2D16 within cells of the ZR. However, adrenal xenobiotic-metabolizing activities in females seem to be further modulated by an inhibitory effect of estrogens.  (+info)

P450 enzyme expression patterns in the NCI human tumor cell line panel. (6/68)

Cytochrome P450 (P450) enzyme expression patterns were determined for a panel of 60 human tumor cell lines, representing nine tumor tissue types, used by the National Cancer Institute (NCI) Anticancer Drug Screening Program. All 60 tumor cell lines displayed significant P450 activity, as well as P450 reductase activity, as determined using the general P450 substrate 7-benzyloxyresorufin. Cell line-specific P450 enzyme patterns were observed using three other P450 substrates, 7-ethoxycoumarin, coumarin, and 7-ethoxyresorufin, each of which was metabolized at a low rate. Using a pattern-matching computer program, COMPARE, correlative relationships were investigated between the arrays of P450 activities and the patterns of cytotoxicity exhibited by a large group of anticancer agents of proven or potential clinical utility. Significant negative correlations between the patterns of P450-dependent 7-benzyloxyresorufin metabolism activity and cell line chemosensitivity were observed for 10 standard anticancer agents (including 6 alkylating agents) and 55 investigational compounds, suggesting a role for P450 metabolism in the inactivation of these agents. Negative correlations between 7-ethoxycoumarin O-deethylation and cell line chemosensitivity to a group of topoisomerase inhibitors were also seen, again suggesting P450-dependent drug inactivation. P450 enzyme profiling may thus aid in interpreting the patterns of drug sensitivity and resistance in the NCI tumor cell panel, and may facilitate the identification of anticancer agents whose activity can be altered via cytochrome P450 metabolism.  (+info)

Characterization by liquid chromatography-nuclear magnetic resonance spectroscopy and liquid chromatography-mass spectrometry of two coupled oxidative-conjugative metabolic pathways for 7-ethoxycoumarin in human liver microsomes treated with alamethicin. (7/68)

The microsomal metabolism of 7-ethoxycoumarin (7-EC) was investigated using liquid chromatography (LC)-NMR and liquid chromatography-mass spectrometry (LC-MS) to characterize the coupling of oxidative-conjugative metabolism events. Within microsomes, cytochromes P450 (P450s) and UDP-glucuronosyltransferases (UGTs) are spatially disparate, each having surface and luminal localization, respectively. To optimize cofactor and substrate transit to UGT without compromising P450 activity, the pore-forming peptide alamethicin was used for microsomal perforation. Aqueous extracts of microsomal incubations containing NADPH and UDP-glucuronic acid were injected for LC-NMR and LC-MS analysis. The analytical complementarity of LC-NMR and LC-MS permitted the identification of four metabolites (M1 to M4). The metabolites M1 and M2 are novel microsomal metabolites for 7-EC, consistent with 3-hydroxylation and subsequent glucuronidation, respectively. Metabolites M3 and M4 were 7-hydroxycoumarin (7-HC) and 7-HC glucuronide, respectively. Viewed collectively, these results illustrate the utility of alamethicin in the examination of coupled oxidative-conjugative metabolism and the synergy of LC-NMR and LC-MS in metabolite identification.  (+info)

Engineering herbicide metabolism in tobacco and Arabidopsis with CYP76B1, a cytochrome P450 enzyme from Jerusalem artichoke. (8/68)

The Jerusalem artichoke (Helianthus tuberosus) xenobiotic inducible cytochrome P450, CYP76B1, catalyzes rapid oxidative dealkylation of various phenylurea herbicides to yield nonphytotoxic metabolites. We have found that increased herbicide metabolism and tolerance can be achieved by ectopic constitutive expression of CYP76B1 in tobacco (Nicotiana tabacum) and Arabidopsis. Transformation with CYP76B1 conferred on tobacco and Arabidopsis a 20-fold increase in tolerance to linuron, a compound detoxified by a single dealkylation, and a 10-fold increase in tolerance to isoproturon or chlortoluron, which need successive catalytic steps for detoxification. Two constructs for expression of translational fusions of CYP76B1 with P450 reductase were prepared to test if they would yield even greater herbicide tolerance. Plants expressing these constructs had lower herbicide tolerance than CYP76B1 alone, which is apparently a consequence of reduced stability of the fusion proteins. In all cases, increased herbicide tolerance results from more extensive metabolism, as demonstrated with exogenously fed phenylurea. Beside increased herbicide tolerance, expression of CYP76B1 has no other visible phenotype in the transgenic plants. Our data indicate that CYP76B1 can function as a selectable marker for plant transformation, allowing efficient selection in vitro and in soil-grown plants. Plants expressing CYP76B1 may also be a potential tool for phytoremediation of contaminated sites.  (+info)

Domain architecture and assignment details (superfamily, family, region, evalue) for cath|current|4i6uD00/3-78 from SCOP2 SCOPe CATH ECOD. Plus protein sequence and external database links.
A new fluorometric method has been developed to measure the relative rates of the 7-ethoxycoumarin O-deethylase activities in periportal and pericentral regions of the liver lobule. The method utilizes a pair of micro-light guides constructed from two strands of 80 µm-diameter glass optical fibers. The micro-light guides are placed in periportal and pericentral regions on the surface of the perfused liver. The increase in tissue fluorescence due to 7-hydroxycoumarin formation from 7-ethoxycoumarin is measured in periportal and pericentral regions by illuminating tissue with light at 360 ± 50 nm and measuring fluorescence at 450 ± 50 nm. Since the steady-state tissue fluorescence due to 7-hydroxycoumarin monitored with a large light guide was found to be directly proportional to the steady-state rate of 7-ethoxycoumarin O-deethylation, the sublobular fluorescence of 7-hydroxycoumarin measured by micro-light guides following infusion of 7-ethoxycoumarin allows one to estimate sublobular rates ...
what are the products of light dependent reactions - 28 images - review for quiz on photosynthesis worland, the two steps of photosynthesis from openstax college, ppt photosynthesis powerpoint presentation id 1090782, science is cool, unit 6 photosynthesis cellular respiration ppt
The light-dependent reactions use light energy to make two molecules needed for the next stage of photosynthesis: the energy storage molecule ATP...
edu/~cem333/EDTATable.html formation constant] (K,sub,f,/sub,) values for metal-EDTA complexes. Note that many heavy metal ions (like Fe,sup,3+,/sup,, Co,sup,2+,/sup,, and Zn,sup,2+,/sup,) are chelated much more strongly than Mg,sup,2+,/sup,. A little bit of EDTA in your reaction will go a long way to keep these evildoers out of trouble and away from your precious biomolecules without interfering with your Mg,sup,2+,/sup,-dependent reactions ...
Human Monocytes/Macrophage Inflammatory Cytokine Changes Following in vivo and in vitro Schistomam manoni Infection Mistire Wolde, 1, 2 Lisa C Laan, 3 Girmay Medhin, 1 Endalemaw Gadissa, 4 Nega Berhe, 1, 5 Aster Tsegaye 2 1Aklilu Lemma Institute of Pathobiology, Addis Ababa University, Addis Ababa, Ethiopia; 2Department of Medical Laboratory Sciences, College of Health Science, Addis Ababa University, Addis Ababa, Ethiopia; 3Department of Molecular Cell Biology and Immunology, VU University Medical Center, Amsterdam, the Netherlands; 4Armauer Hansen Research Institute (AHRI), Addis Ababa, Ethiopia; 5Oslo University Hospital-Ulleval, Centre for Imported and Tropical Diseases, Oslo, NorwayCorrespondence: Mistire WoldeAklilu Lemma Institute of Pathobiology, Addis Ababa University, Addis Ababa, EthiopiaEmail [email protected]: Epidemiological and animal studies indicate that helminth infections have positive effects due to their potential to protect against autoimmune diseases. Here, we
Cytochrome P-450 (P-450) 2A6 was purified by chromatography of human liver microsomes. The final preparation was electrophoretically homogeneous and contained 16 nmol of P-450/mg of protein. The amino-terminal amino acid sequence of the protein (first 13 residues) matched that of the reported cDNA exactly. The UV-visible spectrum indicated that the isolated hemoprotein was in the low-spin form. The protein was recognized by rabbit antibodies raised against rat P-450 2A1, and a rabbit antiserum against the P-450 2A6 preparation was also prepared. With these antibodies, it was estimated that P-450 2A6 accounted for a maximum of 1% of the total P-450 present in the human liver microsomes; the level varied greater than 100-fold among the 20 samples examined. Purified P-450 2A6 catalyzed coumarin 7-hydroxylation and 7-ethoxycoumarin O-deethylation at rates similar to those measured in the human liver sample used to prepare P-450 2A6, and these two microsomal activities were strongly inhibited by the ...
Clotrimazole, an N-substituted imidazole widely used as an antifungal agent, has been shown to both inhibit and induce hepatic cytochrome P-450 and related monooxygenase activities. In this study the profile of hepatic cytochrome P-450 isozyme(s) induced by clotrimazole treatment of male Sprague-Dawley rats was investigated. Clotrimazole administration (100 mg/kg, daily for 4 days, ig) resulted in 86% induction of spectrally detectable cytochrome P-450 in hepatic microsomes. In these microsomes 7-ethoxycoumarin O-deethylase (126%), aminopyrine N-demethylase (176%), benzphetamine N-demethylase (117%), p-nitrophenol hydroxylase (89%), and 7-ethoxyresorufin O-deethylase (62%) activities were significantly induced, whereas aryl hydrocarbon hydroxylase activity remained unchanged. Characterization of cytochrome P-450 isozyme(s) in hepatic microsomes prepared from clotrimazole-treated animals was based on the immunoreactivity of these microsomes with highly specific monoclonal antibodies (MAbs) raised ...
This reagent is a fluorogenic substrate suitable for the continuous determination of cytochrome P450 mixed-function monooxygenases. The product of the reaction is the fluorescent compound 3-cyano-7-hydroxycoumarin (Product No. C 2737). This property has been utilized to determine the activity of CYP1A by measuring the rate of dealkylation of 3-Cyano-7-ethoxycoumarin to this fluorescent product . Fluorescence of 3-cyano-7-hydroxycoumarin occurs at neutral pH with excitation and emission at 408 and 450 nm, respectively . Fluorescent reaction product detection is at least 50-fold more sensitive than that of the product of alkyl resorufin oxidation because of greater rate of turnover of 3-Cyano-7-ethoxycoumarin . The ability to continuously monitor the enzyme reaction at pH 7 is derived from the lower pKa of the 3-cyano-7- hydroxycoumarin product compared to that for 7-ethoxycoumarin . 3-Cyano-7-ethoxycoumarin is a suitable substrate for three of the five principal cytochrome P450 drug metabolizing ...
When chlorophyll a absorbs light energy, an electron gains energy and is excited. The excited electron is transferred to another molecule (called a primary electron acceptor). The chlorophyll molecule is oxidized (loss of electron) and has a positive charge. Photoactivation of chlorophyll a results in the splitting of water molecules and the transfer of energy to ATP and reduced nicotinamide adenine dinucleotide phosphate (NADP). The chemical reactions involved include: condensation reactions - responsible for water molecules splitting out, including phosphorylation (the addition of a phosphate group to an organic compound) oxidation/reduction (redox) reactions involving electron transfer Photosynthesis is a two stage process. 1. The Light dependent reactions, a light-dependent series of reactions which occur in the grana, and require the direct energy of light to make energy-carrier molecules that are used in the second process: light energy is trapped by chlorophyll to make ATP (ph. ...
Sixteen compounds related to GTP were evaluated as inhibitors of bacteriophage-Q beta poly(C)-dependent poly(G) polymerase. Non-phosphorylated compounds, including guanine, guanosine and deoxyguanosine, were inactive. Phosphorylated compounds gave significant inhibition at millimolar concentrations. For nucleotides the feature important for inhibition was the 5′-phosphate chain. Four triphosphates, XTP, ITP, 7-methyl-GTP and 2′-O-methyl-GTP, gave 50% inhibition of both the poly(C)- and poly(U2,C)-dependent reactions at concentrations from 0.1 to 5 mM. XTP was 10-fold more potent an inhibitor of the reaction with poly(U2,C) as template. None of these four compounds was able to substitute for GTP as substrate to a significant extent. The most active compound, 2′-O-methyl-GTP, was a competitive inhibitor (Ki = 0.4 mM) of GTP in the poly(C)-dependent reaction. ...
2 major biochemical reactions that occur in the peroxisome is the mixed function oxidase and the other is a catalase but what 2 enzymes are involved in these reactions?...beta oxidation one of them ...
A study was conducted of the effects of 10 hypolipidaemic agents on peroxisomal and microsomal enzyme activities in primary cultures of rat hepatocytes. Treatment with compounds such as Wy-14,643, tiadenol, nafenopin, BR-931, clofibrate and mono-(2-ethylhexyl)phthalate induced cyanide-insensitive palmitoyl-CoA oxidation (a specific peroxisomal marker enzyme), a polypeptide with a molecular weight of 80,000 associated with peroxisome proliferation, and carnitine acetyltransferase activity, after 70 h of culture. These compounds also maintained hepatocyte cytochrome P-450 levels and markedly induced lauric acid hydroxylation, whereas little effect was observed on 7-ethoxycoumarin O-deethylase. Studies with metyrapone, which also maintains cytochrome P-450, suggested that treatment with the hypolipidaemic agents resulted in the formation of different form(s) of cytochrome P-450 to those present in control cultures. Regression analysis demonstrated a high correlation between the induction of the peroxisomal
Natural Electron ACCEPTORS Nicotinamide Adenine Dinucleotide Phosphate (NADP) used in photosynthesis in chloroplasts NADP + + 2H + + 2e - NADPH + H + Ferredoxin the most difficult to reduce (and most easily oxidised) Cytochromes Conjugate proteins which contain a haem group. The iron atom undergoes redox reactions Fe 3+ + e - Fe 2+ NB The iron atom in the haem group of haemoglobin does not go through a redox reaction Haemoglobin is oxygenated or deoxygenated Reduction Oxidation Reduction Oxidation © 2010 Paul Billiet ODWSODWS
Atlas, S A.; Diwan, B A.; and Nebert, D W., "Inducible monooxygenase activities and 3-methylcholanthrene- -initiated tumorigenesis in mouse recombinant inbred sublines." (1976). Subject Strain Bibliography 1976. 2211 ...
Coumarins: Biology, Applications and Mode of Action predominantly focuses on the parent compound, coumarin, and its main metabolite in humans, 7-hydroxycoumarin. It describes in detail every facet of these compounds including history, toxicology, chemistry, metabolism, analysis, clinical, veterinary and other applications, their roles as immunomodulatory agents and speculates on their mode of action.
Download Free Full-Text of an article EFFECTS OF 3 - METHYL CHOLANTHEREN ON LIVER MICROSOMAL MIXED FUNCTION OXIDASE ACTIVITIES OF ACIPENSER PERSICUS
Hill Reaction Chloroplasts contained the naturally occurring electron acceptor NADP+ and that it was reduced to NADPH2 in the light by addition of electrons and hydrogen ions. The hydrogen ions for the reduction are provide by water molecule which split into hydrogen ions and electrons releasing the oxygen (photolysis of water). The chloroplasts supplied with ADP and inorganic phosphate, manufacture .... Read More » ...
I m confused about cyclic and non-cyclic photophosporilation. Do they happen at the same time? And what connects them? Thanks a lot for the help...
Kinetic and inhibitor studies using cDNA-expressed enzymes and human liver microsomes have characterized the specificity of a range of cytochrome P450 (CYP) 1A substrate and inhibitor probes towards the two isoforms comprising this subfamily. Expressed CYP1A1 and CYP1A2 both catalyzed the O-deethylation of phenacetin, although the apparent Km was about 4-fold lower for CYP1A2 (25 vs. 108 microM). Phenacetin O-deethylation exhibited biphasic kinetics in human liver microsomes, and the apparent Km for the high-affinity component (9 +/- 6 microM) was consistent with the involvement of CYP1A2 in this reaction. The prototypic CYP1A xenobiotic inhibitor and substrate probes alpha-naphthoflavone, ellipticine, 7-ethoxycoumarin and 7-ethoxyresorufin all inhibited CYP1A1- and CYP1A2-mediated phenacetin O-deethylation as well as the high-affinity component of human liver phenacetin O-deethylase activity. alpha-Naphthoflavone and 7-ethoxycoumarin were, however, approximately 10-fold more potent as ...
Author: Garda, H. A. et al.; Genre: Journal Article; Published in Print: 1994-12-07; Keywords: CYTOCHROME P450 LM2; SUBSTRATE BINDING; MICROHETEROGENEITY; MULTIPLICITY|br/|; Title: Heterogeneity in rabbit liver cytochrome P-450 LM2 observed by cation exchange HPLC: Partial biochemical characterization of the two major LM2 subfractions
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Bardag-Gorce, F., Yuan, Q.X., Li, J., French, B.A., Fang, C., Ingelman-Sundberg, M., French, S.W., 2000. The effect of ethanol-induced cytochrome p4502E1 on the inhibition of proteasome activity by alcohol. Biochem. Biophys. Res. Commun. 279, 23-29.. Bondoc, F.Y., Bao, Z., Hu, W.Y., Gonzalez, F.J., Wang, Y., Yang, C.S., Hong, J.Y., 1999. Acetone catabolism by cytochrome P450 2E1: studies with CYP2E1-null mice. Biochem. Pharmacol. 58, 461-463.. Cederbaum, A.I., 2014. Methodology to assay CYP2E1 mixed function oxidase catalytic activity and its induction. Redox Biol. 2C, 1048-1054.. Cheng, J., Chen, C., Kristopher, K.W., Manna, S.K., Scerba, M., Friedman, F.K., Luecke, H., Idle, J.R., Gonzalez, F.J., 2013. Identification of 2-piperidone as a biomarker of CYP2E1 activity through metabolomic phenotyping. Toxicol. Sci. 135, 37-47.. Cheung, C., Gonzalez, F.J., 2008. Humanized mouse lines and their application for prediction of human drug metabolism and toxicological risk assessment. J. Pharmacol. Exp. ...
Interindividual variations in the level and activity of cytochrome P-450 enzymes were investigated in the liver microsomes of 30 Japanese and 30 Caucasian patients. The P-450 enzymes used in this study included P-450 1A2, 2A6, 2B6, 2C, 2D6, 2E1 and 3A, and the monooxygenase activities determined were 13 typical P-450 substrates and 9 procarcinogens. Although the total P-450 content was higher in Caucasian (mean, 0.43 nmol/mg of protein) than in Japanese populations (mean, 0.26 nmol/mg of protein), the relative levels (percent of total P-450) of individual forms of P-450 determined immunochemically were not very different except that P-450 2A6 and 2B6 levels were higher in the Caucasians. About 70% of liver P-450 could be accounted for by P-450 1A2, 2A6, 2B6, 2C, 2D6, 2E1 and 3A proteins, and P-450 3A (about 30% of total P-450) and 2C (about 20%) enzymes were found to be the major forms. Considerable levels of P-450 1A2 (about 13%) and 2E1 (about 7%) could be determined, whereas the P-450 2A6 ...
Lee, S.-M. and Clemens, M. G. (1992), Effect of α-tocopherol on hepatic mixed function oxidases in hepatic ischemia/reperfusion. Hepatology, 15: 276-281. doi: 10.1002/hep.1840150217 ...
We measured aryl hydrocarbon hydroxylase (AHH) in cultured human lymphocytes. A striking seasonal variation in AHH activity was observed with induced AHH activity levels from January through May measuring approximately 20% of the values during the remainder of the year. AHH inducibility was determined by comparing lymphocytes from the same person cultured with and without the inducer 3-methylcholanthrene. If measurements are limited to the summer and fall seasons when AHH activity is high, AHH inducibility is reproducible for most persons with repeat determinations on the same person averaging 11% from the mean. The values of AHH inducibility in 53 persons ranged from 0.9 to 5.0, but the distribution of values did not fall into three distinct, nonoverlapping classes as reported by others. We were not able to determine the distribution of AHH inducibility in lung cancer patients since lymphocytes from less than half of the patients tested could be successfully cultured.
The response of intestinal monooxygenases to dietary polycyclic aromatic hydrocarbon (PAH) exposure was evaluated in spot (Leiostomus xanthurus), a marine teleost fish. Ethoxyresorufin O-deethylase (EROD) and aryl hydrocarbon hydroxylase (AHH) activities were highest in the pyloric caeca and in the proximal half of the intestine. Intestinal microsomes from fish given control diets had very low levels of EROD and AHH activities relative to those in liver. After exposure to a diet containing 10 mg of 3-methylcholanthrene/kg of food, the levels of intestinal EROD and AHH activities increased 36-fold and 17-fold, respectively, such that intestinal monooxygenase activity exceeded that of the liver, which was not induced by this treatment. A significant increase in intestinal monooxygenase activity occurred in fish receiving dietary benzo[a]pyrene (BP) at concentrations as low as 10 micrograms of BP/kg food. A 5-fold increase in intestinal AHH and EROD activities was observed within 3 hr after ...
So how can these factors have an effect on the rate of photosynthesis? Lets start off with the light intensity. When the light intensity is poor, there is a shortage of ATP and NADPH, as these are products from the light dependent reactions. Without
Hey , I was wondering since you had your nose done with Dr. Hsu. Do you have his email address? How much did it cost you? I also have a flat-ish nose and I m considering rib grafting but I m not sure. I heard your nose will be stiffer or hard, is it..
Experimentally measured reaction rates are temperature dependent; usually, characterized by an Arrhenius rate law,R(T) =Z exp(-T_a/T).Yet for numerical simulations of detonation waves in plastic binded explosives (PBX) empirical pressure dependent reaction rates, such as Forest fire or the Ignition and Growth model, are typically used.
Oganessian, Yu. Ts.; Utyonkov, V. K.; Lobanov, Yu. V.; Abdullin, F. Sh.; Polyakov, A. N.; Shirokovsky, I. V.; Tsyganov, Yu. S.; Mezentsev, A. N.; Iliev, S.; Subbotin, V. G.; Sukhov, A. M.; Subotic, K.; Ivanov, O. V.; Voinov, A. N.; Zagrebaev, V. I.; Moody, K. J.; Wild, J. F.; Stoyer, N. J.; Stoyer, M. A.; Lougheed, R. W.
Rabbit anti-rat cytochrome P450 enzyme CYP1A1 (polyclonal antibody). Involved in metabolism of xenobiotics, drugs and polyunsaturated fatty acids. Implicated in metabolism of some polycyclic hydrocarbons to carcinogenic intermediates. CODE NUMBER: R2U.. QUANTITY: 0.1 mL.. SPECIFICITY: Reacts with rat cytochrome P450 enzyme CYP1A1 in hepatic microsomal fraction. No cross-reactivity with other cytochrome P450 enzymes including CYP1A2.. IMMUNOGEN: Synthetic peptide.. SUGGESTED APPLICATIONS: Western blot, immunohistochemistry on frozen and formaldehyde treated sections. Optimal working dilutions must be determined by end user.. SPECIES REACTIVITY: Rat.. FORMAT: Rabbit antiserum.. PRESENTATION: Liquid. No preservatives.. STORAGE/HANDLING: Maintain at -20°C in undiluted aliquots for up to 12 months. Avoid repeated freeze/thaw cycles.. For research use only; not for use in diagnostic procedures. Not for human or animal consumption.. To purchase this product, please email ...
Rabbit anti-rat cytochrome P450 enzyme CYP2D1 (polyclonal antibody). O-demethylation of xenobiotics, CYP2D6 is involved in the metabolism and elimination of approximately 25% of clinically used drugs in humans1. Primarily expressed in the liver and areas of the CNS. CYP2D1 and CYP2D4 have a similar function in rats2.. CODE NUMBER: RK05.. QUANTITY: 0.1 mL.. SPECIFICITY: Reacts with rat cytochrome P450 enzyme CYP2D1 in hepatic microsomal fraction.. IMMUNOGEN: Synthetic peptide.. SUGGESTED APPLICATIONS: Western blot, immunohistochemistry on frozen and formaldehyde treated sections. Optimal working dilutions must be determined by end user.. SPECIES REACTIVITY: Rat.. FORMAT: Rabbit antiserum.. PRESENTATION: Liquid. No preservatives.. STORAGE/HANDLING: Maintain at -20°C in undiluted aliquots for up to 12 months. Avoid repeated freeze/thaw cycles.. For research use only; not for use in diagnostic procedures. Not for human or animal consumption.. CYP2D1 is also known as CYPIID1, Cyp2d-1, Cyp2d9 and ...
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... map kinase kinase 7 MeSH D08.811.913.696.620.682.725.300 --- proto-oncogene proteins c-fes MeSH D08.811.913.696.620.682.725.400 ... map kinase kinase 7 MeSH D08.811.913.696.620.682.700.567 --- mitogen-activated protein kinases MeSH D08.811.913.696.620.682. ... cholesterol 7 alpha-hydroxylase MeSH D08.811.682.690.708.170.915.212 --- cholesterol side-chain cleavage enzyme MeSH D08.811. ... cholesterol 7 alpha-hydroxylase MeSH D08.244.453.915.212 --- cholesterol side-chain cleavage enzyme MeSH D08.244.453.915.400 ...
Male Sprague-Dawley rats were fed on purified diets supplemented with 50-500 ppm indole-3-carbinol (I3C), a compound present in cruciferous vegetables, or with 25% Brussels sprouts (Brassica oleracea) for 10 days after a 1-wk equilibration on a purified diet. Cytosolic and microsomal fractions were …
... map kinase kinase 7 MeSH D08.811.913.696.620.682.725.300 --- proto-oncogene proteins c-fes MeSH D08.811.913.696.620.682.725.400 ... map kinase kinase 7 MeSH D08.811.913.696.620.682.700.567 --- mitogen-activated protein kinases MeSH D08.811.913.696.620.682. ... cholesterol 7 alpha-hydroxylase MeSH D08.811.682.690.708.170.915.212 --- cholesterol side-chain cleavage enzyme MeSH D08.811. ... cholesterol 7 alpha-hydroxylase MeSH D08.244.453.915.212 --- cholesterol side-chain cleavage enzyme MeSH D08.244.453.915.400 ...
TY - JOUR. T1 - Activities of glutathione-S-transferase and ethoxycoumarin-O-deethylase in tissues of camels, sheep, goats and rats. AU - El Sheikh, H. A.. AU - Ali, B. H.. AU - Homeida, A. M.. AU - Hapke, H. J.. PY - 1991. Y1 - 1991. N2 - 1. The activities of the drug metabolizing enzymes ethoxycoumarin-O-deethylase, glutathione-S-transferase, and protein concentrations were measured in vitro in the liver, kidney and duodenal mucosa of camels, sheep, goats and rats. 2. Enzyme activities were generally higher in the liver than in the kidney and duodenal mucosa in the four species studied. 3. The activities of ethoxycoumarin-O-deethylase and glutathione-S-transferase in liver of male kids were about one third and half of that in adult male goats, respectively.In the kidney and duodenal mucosa of male kids, the activity of glutathione-S-transferase was about 70% and 53% of that in the mature male goat, respectively. In the latter tissues, however, there was no detectable activity of ...
The majority (7/10) of the species had total P450 content between 0.1 and 0.5 nmol/mg, and cytochrome b5 content between 0.025 ... The majority (7/10) of the species had total P450 content between 0.1 and 0.5 nmol/mg, and cytochrome b5 content between 0.025 ... The majority (7/10) of the species had total P450 content between 0.1 and 0.5 nmol/mg, and cytochrome b5 content between 0.025 ... The majority (7/10) of the species had total P450 content between 0.1 and 0.5 nmol/mg, and cytochrome b5 content between 0.025 ...
Lin, C. K. & Berndt, C. C., Jan 1995, In : Journal of Materials Science. 30, 1, p. 111-117 7 p.. Research output: Contribution ... Carter, T. H., Dominguez, N., Zeng, L. & Kung, H. J., Sep 10 1995, In : Virology. 212, 1, p. 277-283 7 p., 71484.. Research ... Lin, K. L., Wang, H. S. & Lui, T. N., Jul 1995, In : Journal of Ultrasound in Medicine. 14, 7, p. 537-541 5 p.. Research output ... S., 1995, In : Journal of the Chinese Chemical Society. 42, 3, p. 561-567 7 p.. Research output: Contribution to journal › ...
Increases in P450 content and alkoxycoumarin dealkylase activity in PB-BNF-induced rat S9. a, P450 contents; b, alkoxycoumarin ... Consequently, alkoxycoumarin O-dealkylase activity known as markers for CYP activity and protein expression of CYP1A1, CYP1A2, ... Based on the results of the cell growth assay and in vitro micronucleus test of the dose range-finding test, 3 to 7 dose levels ... O-dealkylase (ACD) activities; Open bars, untreated rat S9; Gray bars; combination of phenobarbital and 5,6-benzoflavone- ...
Western blot/densitometry analysis revealed a 4.8 times lower binding of Mab 1-7-1 to cDNA-expressed CYP1A2 than to CYP1A1. The ... and 7-ethoxyresorufin o-deethylase (EROD) were estimated in microsomes of Hep G2 cells infected with a recombinant vaccinia ... 1-7-1 displayed a striking difference between its immunoblotting and inhibitory effects. ... Kinetics of benzo[alpha]pyrene hydroxylase (AHH), 7-methoxyresorufin o-demethylase (MROD), and 7-ethoxyresorufin o-deethylase ( ...
Reductive metabolism of diaziquone (AZQ) in the S9 fraction of MCF-7 cells. II. Enhancement of the alkylating activity of AZQ ... 7-Alkoxycoumarin O-Dealkylase, antagonists & inhibitors, Aminopyrine N-Demethylase, Animals, Cytochrome P-450 Enzyme System, ...
5-Tetrahydro-7,8-dihydroxy-1-phenyl-1H-3-benzazepine D3.438.79.800 D3.633.100.79.800 2-Aminopurine D3.438.759.138.50 D3.633. ... Ataxin-7 D12.776.641.69.901 D12.776.631.69.901 Ataxins D12.776.641.69 D12.776.631.69 Atracurium D3.438.531.85.61 D3.633.100.531 ... 7,11b-hexahydro-3-isobutyl-9,10-dimethoxy- D3.438.834.700 D3.633.100.834.700 4-Hydroxyaminoquinoline-1-oxide D3.438.810.50.440 ... 7-Alkoxycoumarin O-Dealkylase D8.811.682.690.708.170.40.24 D8.811.682.690.708.170.10.24 8-Bromo Cyclic Adenosine Monophosphate ...
The major metabolite of O-dealkylase activities of cytochrome P 450, 7-HC, was conjugated with glucuronic acid or sulfate ... demonstrated the effects of model inducing agents on hepatic phase I-phase II integrated drug metabolism using alkoxycoumarin ... Total phase II activity was assessed using 7-HC as the primary substrate and found to be 7-fold higher than total phase I ... Heroin was found in 7 of 20 heroin user specimens. Generally, the 6-acetylmorphine concentration in hair was higher than that ...
Dealkylase, 7-Ethoxycoumarin use 7-Alkoxycoumarin O-Dealkylase Dealkylation Dealkylations use Dealkylation ...
Dealkylase, 7-Ethoxycoumarin use 7-Alkoxycoumarin O-Dealkylase Dealkylation Dealkylations use Dealkylation ...
Dealkylase, 7-Ethoxycoumarin use 7-Alkoxycoumarin O-Dealkylase Dealkylation Dealkylations use Dealkylation ...
CYP3A4 is a member of the CYP3A family of genes located on chromosome 7. The CYP3A subfamily of enzymes is responsible for the ... been working out hard for over 7 years. only anabolic ive ever taken was megaplexx. im about to start my first true anabolic. ... CYP3A5 is a member of the CYP3A family of genes located on chromosome 7. The CYP3A subfamily of enzymes responsible for the ... The CYP450 kits utilize MS, specifically MRM methodology, to monitor for the presence of up to 7 specific CYP450 isoforms, and ...
  • Ethoxycoumarin O-deethylase (ECOD) and aminopyrine N-demethylase (APND) rates in these 7 species were 0.23-2.1 nmol/min/mg and 0.5-11 nmol/min/mg, respectively, similar to rates in many temperate fish species. (elsevier.com)