some random values for future research pdf

Tài liệu Báo cáo khoa học: Pathways and products for the metabolism of vitamin D3 by cytochrome P450scc docx

Ngày tải lên : 18/02/2014, 17:20

... P450scc resulted in the formation of 20,23-dihydroxyvitamin D3 (RT = 30 min) and trihydroxyvitamin D3 (RT = 22 min) (Fig 4A) A small lag (0– min) was seen in the time course for formation of trihydroxyvitamin ... correlations for 3-CH and 23-CH; (B) expansion of proton–proton TOCSY correlations for 3-CH and 23-CH; (C) expansion of proton–carbon HSQC showing groups having correlation to 3-CH and 23-CH (for details, ... 17a,20-dihydroxyvitamin D3 We have therefore identiﬁed this monohydroxyvitamin D3 as 17a-hydroxyvitamin D3 This product is only seen for the metabolism of D3, and not for the metabolism of 20-hydroxyvitamin...

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Tài liệu Báo cáo khoa học: Cytochrome P450 Cyp4x1 is a major P450 protein in mouse brain doc

Ngày tải lên : 19/02/2014, 07:20

... to storage at )80° C for the isolation of RNA by the Triazol method (Invitrogen), or used directly for the preparation of microsomes New Zealand White rabbits were used for immunization with ... and the 1.2-kb fragment was radiolabelled with random primers for screening an aorta cDNA library Full-length clones were conﬁrmed by sequencing For production of human CYP4x1 antigen, the cDNA ... into pRSETc (Invitrogen) for expression of amino acids 327–509 of CYP4x1 as an N-terminally histidine-tagged fusion protein in bacteria A probe for RNAase protection for mouse Cyp4x1 was obtained...

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Tài liệu Báo cáo khóa học: Point mutations associated with insecticide resistance in the Drosophila cytochrome P450 Cyp6a2 enable DDT metabolism doc

Ngày tải lên : 19/02/2014, 12:20

... spectrophotometry measurements for each construction were divided by the relevant data obtained with the wild-type enzyme These operations, for each construction, gave normalized values for the apo- and holoenzymes ... to be responsible for the speciﬁcity of the reactions catalyzed In insects, little information is available about the structure of cytochrome P450 A recent report established some structure-activity ... methanol followed by precipitation of the proteins and incubation at °C for 15 The mix was then centrifuged at 13 000 g for 15 at °C For DDT metabolism, 150 lL of the supernatant were analyzed by HPLC...

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Tài liệu Báo cáo khoa học: Models and mechanisms of O-O bond activation by cytochrome P450 A critical assessment of the potential role of multiple active intermediates in oxidative catalysis doc

Ngày tải lên : 19/02/2014, 16:20

... has been evaluated as a potential model for deformylation reactions brought about by steroidogenic P450s: mass-spectral analysis unveiled formate to be formed in about an equimolar amount with ... activated-BLM formation [237,238] The accepted mode of reactivity toward DNA is hydrogen atom abstraction from the C4Â position of the DNA deoxyribose sugar, for which multiple scenarios have been set forth ... decarbonylation of the 19-aldehyde intermediate to release formic acid with the concomitant production of estrone [268] When human placental microsomes fortied with deuteriated androgen precursors in the...

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Báo cáo khoa học: Arabidopsis thaliana CYP77A4 is the ﬁrst cytochrome P450 able to catalyze the epoxidation of free fatty acids in plants potx

Ngày tải lên : 07/03/2014, 03:20

... spotted onto TLC (A) Experiment performed with microsomes (B) Experiment performed with boiled microsomes (C) Experiment performed with cytosol (D) Experiment performed with boiled cytosol Peak ... their formation required the presence of NADPH in the incubation They were also not formed on incubation with microsomes from yeast transformed with a void plasmid (Fig 2C) or with boiled microsomes ... It was not formed in the absence of NADPH (Fig 1A), with microsomes from yeast transformed with a void plasmid (Fig 1C) or CYP77A4, an epoxy fatty acid-forming enzyme with boiled microsomes (Fig...

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Báo cáo khoa học: Inter-ﬂavin electron transfer in cytochrome P450 reductase – effects of solvent and pH identify hidden complexity in mechanism potx

Ngày tải lên : 07/03/2014, 06:20

... pH-dependent H2O amplitudes to Eqn (4) gave pKa,app values of 7.8 0.1 for the rst, 7.5 0.3 for the second and 7.9 0.3 for the third phase, respectively These values are within error of those obtained ... providing the relevant information for each of the listed possibilities To determine whether the anionic sq species is formed at high pH, stopped-ow PDA studies were performed, in which oxidized ... presteady-state rate constants measured for the reductive half-reaction of CPR Whereas kcat values between 12 and 48ặs)1 have been reported for intact human CPR and of up to 80ặs)1 for the enzyme missing the...

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Báo cáo khoa học: D88A mutant of cytochrome P450nor provides kinetic evidence for direct complex formation with electron donor NADH ppt

Ngày tải lên : 07/03/2014, 15:20

... a few water molecules is + formed upon Fe3 –NO complex formation, and that the network should play a key role in providing a proton that is required for intermediate formation [9,10] As shown ... formation of the mutant protein (Fig 4), suggesting that the Table Kinetic parameters for the reduction step for P450nor wild-type and mutant enzymes kobs, Observed ﬁrst-order rate constant for ... B¢-helix and F,G-loop form the entrance of the pocket There is an intriguing tendency in the distribution of charged amino acid residues that form the putative access channel for NADH Most of the...

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Báo cáo khoa học: Testosterone 1b-hydroxylation by human cytochrome P450 3A4 pdf

Ngày tải lên : 07/03/2014, 16:20

... systems (Table 2) Rates of formation of the products were similar The 1b-hydroxy product accounts for 5% of all testosterone products formed in both systems The formation of 1b-hydroxytestosterone ... delay s, and eight scans for each of the 512 increments The same parameters were used for phase sensitive 1H-1H NOESY with H2O suppression on the water signal except for the number of scans (32), ... similar to ours However, the J1a,2a and J1a,2b values differ Our assignments are also consistent with those reported for 1a-hydroxytestosterone, except for the differences at and near C-1 (http://www...

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Báo cáo khoa học: Kinetic and binding studies with purified recombinant proteins ferredoxin reductase, ferredoxin and cytochrome P450 comprising the morpholine mono-oxygenase from Mycobacteriumsp. strain HE5 ppt

Ngày tải lên : 07/03/2014, 16:20

... was performed with whole-cell DNA as the template according to the following parameters: 94 °C for min; 10 cycles of 94 °C for 15 s, 52 °C for 30 s, 72 °C for 30 s; 20 cycles of 94 °C for 15 ... the inactive P420 form, CO difference spectra of NHisP450mor showed no peak at 425 nm, indicating that the protein was puriﬁed in its active form which was stable at )20 °C for over months Even ... used For instance, in this study a 60-fold higher Km of FdRmor for Fdmor was measured with cytochrome c as the electron acceptor, compared with NBT reduction However, the low Km value of FdRmor for...

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Báo cáo khoa học: The cytochrome P450scc system opens an alternate pathway of vitamin D3 metabolism docx

Ngày tải lên : 07/03/2014, 21:20

... additional derivatives, some of which are metabolically active with CYP24A being involved in production of some of these compounds [8,13–16] P450scc (CYP11A1), the enzyme that performs cleavage of ... proportion of product P2 varied between incubations, being barely detectable in some Time courses for product formation based on the intensity of spots following TLC showed no further accumulation ... opens a novel pathway for the metabolism of secosteroids According to kinetic data generated by Guryev et al [18] the rate (Vmax) for P450scc processing vitamin D3 is 43% of that for cholesterol,...

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Báo cáo Y học: Baboon cytochrome P450 17a-hydroxylase/17,20-lyase (CYP17) Characterization of the adrenal microsomal and cloned enzymes docx

Ngày tải lên : 08/03/2014, 09:20

... slower for baboon CYP17 than for the human enzyme (Fig 7) The Km and V values for PREG utilization by baboon CYP17 were 0.9 lM and 0.45 nmolÆh)1Æmg)1 protein, respectively (Fig 8) These values ... accumulation of 17-OHPREG before DHEA formation was observed, was not as pronounced as that seen for the conversion of PREG by baboon CYP17 A comparison of the ratios of DHEA:17-OHPREG formation during ... deoxyribonucleic acid for human adrenocortical 17a-hydroxylase: a probe for analysis of 17a-hydroxylase deﬁciency Mol Endocrinol 1, 348–354 Bradford, M.M (1976) A rapid and sensitive method for the quantitation...

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Báo cáo Y học: Substrates modulate the rate-determining step for CO binding in cytochrome P450cam (CYP101) A high-pressure stopped-ﬂow study pdf

Ngày tải lên : 08/03/2014, 23:20

... stopped-flow for P450 CO binding (Eur J Biochem 269) 2991 Three shots at each pressure were taken and fitted The kon values for the same pressure were averaged The averaged values were used for further ... is the regression coefficient for the linear regression analysis: slow phase (0.92 for P < 1200 bar, 0.75 for P > 1200 bar); fast phase (0.72 for P < 1000 bar, 0.93 for P > 1000 bar) Table the ... P450 is therefore indicative rather for a high solvent accessibility of the heme pocket than for a diffusion limited process Subconformers of P450cam have different kon and DV # for CO binding...

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Báo cáo khoa học: Kinetic deuterium isotope effects for 7-alkoxycoumarin O-dealkylation reactions catalyzed by human cytochromes P450 and in liver microsomes Rate-limiting C-H bond breaking in cytochrome P450 1A2 substrate oxidation pdf

Ngày tải lên : 16/03/2014, 13:20

... intrinisic isotope effects The values for 7-OMe O-demethylation, measured by MS, were 9.4 and 9.6 for P450s 1A2 and 2E1, respectively (Table 1) The corresponding values were 6.1 for both P450s 1A2 and ... value was high for P450 1A2 (9.5); with 7-OMe coumarin the value for P450 1A2 was 10.6 and for P450 2E1 was 7.7 The value of these measurements lies in their comparison with the values measured ... measurements for the intramolecular and intermolecular competitive experiments For 7-OEt coumarin O-deethylation, the values DV ¼ 3.0 ± 0.2 and D(V ⁄ K) ¼ 2.5 ± 0.9 were obtained The rate of formation...

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Báo cáo khoa học: The ﬁrst cytochrome P450 in ferns Evidence for its involvement in phytoecdysteroid biosynthesis in Polypodium vulgare doc

Ngày tải lên : 16/03/2014, 23:20

... differential spectrum Values shown are mean ± SD for triplicate experiments matic activity in microsomes, but this activity could be calculated in vivo by measuring the transformation of exogenously ... analysed after 24 h using HPLC The biotransformation ratio was normalized to untreated calli, assigned a relative activity of Values are shown as mean ± SD for triplicate experiments Fig Bioconversion ... (20 E per h) is represented by squares Values are shown as mean ± SD for triplicate experiments In P vulgare calli, E is oxidized to 20E up to 80% of transformation (Fig 2), which is independent...

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Báo cáo khoa học: Two CCAAT/enhancer binding protein sites in the cytochrome P4503A1 locus Potencial role in the glucocorticoid response ppt

Ngày tải lên : 17/03/2014, 09:20

... probe for additional 20 Supershift reactions were performed with lL of anti-C/EBP (14AA, Santa Cruz Biotechnology) which was added to the reaction media, that were kept on ice for 30 before addition ... dATP using T4 polynucleotide kinase test for unequal N (Spjotvoll/Stoline test) All analysis were performed using the StatSoft Inc (1995) STATISTICA FOR WINDOWS software Nuclear extracts Results ... activity and protein content (BCA reagent, Pierce, Rockfort, IL, USA) The cell extracts were normalized for the total amount of protein prior to performing the luciferase assay, as C/EBP expression...

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Báo cáo khoa học: Key substrate recognition residues in the active site of a plant cytochrome P450, CYP73A1 ppt

Ngày tải lên : 17/03/2014, 10:20

... 100% activity is 287 pkatÆmg)1 microsomal protein for CA, 311 pkatÆmg)1 for NA, 38.8 pkat mg)1 for I2C, 20.4 pkat mg)1 for I3C, 6.6 pkat mg)1 for 7MC n.d not determined Mutant CA NA I2C P1/P2 ... observed for a few ligands after modiﬁcation of the protein The most notable increases are 15-fold for N302D with phenylalanine, 12-fold for I371K with 2-phenoxyacetamidine, and 10-fold for I371F ... etype I/Ks ratio calculated for each complex The values listed are relative to the wild-type for each ligand Standard deviations (not shown) are less than 12% of these values Unexpectedly, the K484M...

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Báo cáo khoa học: Metabolism of N-methyl-amide by cytochrome P450s Formation and characterization of highly stable carbinol-amide intermediate pdf

Ngày tải lên : 22/03/2014, 16:20

... of residue NCH2OH group, in two different conformers Conformational analysis performed, as previously published [35], suggests two possible stable conformations of the N-hydroxymethyl group (above ... groups of values from Table should be highlighted: the barriers for the deformylation of carbinolamines are 30 kcalặmol)1, whereas the reaction requires 53 kcalặmol)1 to proceed for carbinol-amides ... et al Scheme (A) Free enthalpy prole for the mechanism of deformylation of N,N,N-ethylmethyl-hydroxymethyl-amine (B) Energy prole for the mechanism of deformylation of N,N-methyl-hydroxymethyl-acetamide...

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Báo cáo khoa học: Cytochrome P450 metabolizing fatty acids in plants: characterization and physiological roles pptx

Ngày tải lên : 22/03/2014, 16:21

... shown in spaceﬁlling format From Rapusinghe et al [16] 198 formation of dicarboxylic FAs Using microsomal fraction of V sativa, Weissbart et al [10] showed that x-hydroxylases form epoxides when ... peroxisomes [45] which have an important role in responses to pathogens [46] Induction of mammalian x-hydroxylases by cloﬁbrate and peroxisome proliferation occur via activation of a peroxisome ... hydroxylase HO OH OH HOOC D Fig Formation of antifungic 12,13,17-trihydroxyoctadeca-9-enoic acid in microsomes of Arabidopsis thaliana Putative pathway leading to the formation of 12,13,17-trihydroxyoctadeca-9-enoic...

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Báo cáo khoa học: The role of cytochrome P450 monooxygenases in microbial fatty acid metabolism pdf

Ngày tải lên : 22/03/2014, 16:21

... P450s Some P450s acting on fatty acids are hidden between related proteins acting on totally different substrates CYP106A1 or BM-1 for B megaterium, for example, hydroxylates fatty acids, but information ... and turn it into an ideal model for spectroscopic and structural studies The derived models for the heme–substrate interactions indeed gave substantial input for the understanding of mammalian ... be observed for the bacterial P450alk enzymes For example, Sphingomonas sp HXN200 possesses ﬁve CYP153 genes, three of which show activity towards C5–C10 alkanes, whereas no afﬁnity for these substrates...

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