Search results for "hydroxylation"
showing 10 items of 102 documents
Xenobiotic metabolizing enzyme activities and viability are well preserved in EDTA-isolated rat liver parenchymal cells after cryopreservation
1995
Rat liver parenchymal cells (PC) were isolated by EDTA perfusion and were purified by a subsequent Percoll centrifugation. The isolated PC had a viability of 95%, as judged by trypan blue exclusion. Freshly isolated PC were cryopreserved with an optimized protocol in a computer-controlled freezer. After thawing, the PC still retained a viability of 89%. The activities of representative xenobiotic metabolizing enzymes were compared between freshly isolated and cryopreserved PC after thawing. The cytochrome P450 content and the cytochrome P450 2C11 isoenzyme activity, determined by hydroxylation of testosterone in intact cells, were not affected by the cryopreservation. The following phase II…
Constitutive and inducible expression of CYP enzymes in immortal hepatocytes derived from SV40 transgenic mice
2003
1. The expression of liver-specific transcription factors and cytochrome P450 (CYP) enzymes have been studied in three new hepatocyte-like cell lines derived from SV Delta 202 transgenic mice: AMH-Delta 202 (adult mouse hepatocytes), TAMH-Delta 202 (tumour-derived adult mouse hepatocytes) and NMH-Delta 202 (newborn mouse hepatocytes). 2. mRNA levels of liver-enriched transcription factors such as D-element binding protein (DBP), liver-enriched transcription activating protein (LAP) and the hepatic nuclear factors (HNF) 1, 2 and 3 in all Delta 202 transgenic hepatocyte lines were similar to those in the wild-type liver and in primary mouse hepatocytes. 3. Analysis of basal CYP activities and…
Polybrominated methoxy diphenyl ethers (MeO-PBDEs) in fish and guillemot of Baltic, Atlantic and Arctic environments
2003
Arctic cod liver samples from Vestertana Fjord at the Arctic coast of Norway, salmon and guillemot samples from the Baltic Sea and the Atlantic Ocean, and salmon and lamprey larva samples from Kymijoki River in southern Finland were analysed for the occurrence of tri-, tetra- and pentabromomethoxy diphenyl ethers and their concentration levels were estimated. These compounds have previously been identified by other research groups in salmon, seal and dolphin samples. The aim of this study was to find out a possible temporal trend in the concentrations of these compounds in the cod liver samples from years 1987-1998 and to investigate the possible spatial differences in the concentrations in…
Biotransformations of monoterpenes by photoautotrophic micro-organisms.
2014
Summary Monoterpenes are widely used in food technology, cosmetic and pharmaceutical industries and as compounds of agricultural importance. It is known that compounds comprising this class can be transformed by a variety of organisms, namely by: bacteria, fungi, yeasts, plants or isolated enzymes. Biotransformations, as one of the most important tools of green chemistry, allow obtaining new products using whole cells of micro-organisms or isolated enzymes in mild reaction conditions. Therefore, biotransformations of monoterpenes, by different type of reaction such as: epoxidation, oxidation and stereoselective hydroxylation, resulted in the production of so desired, enantiomerically define…
Stereoselective Access to Fluorinated and Non-fluorinated Quaternary Piperidines: Synthesis of Pipecolic Acid and Iminosugar Derivatives
2012
The preparation of optically pure quaternary piperidines, both fluorinated and non-fluorinated, has been achieved from a chiral imino lactone derived from (R)-phenylglycinol. In the case of the fluorinated derivatives, the addition of (trifluoromethyl)trimethylsilane (TMSCF(3)) followed by iodoamination and migration of the CF(3) group allowed access to four derivatives of α-(trifluoromethyl)pipecolic acid. A theoretical study of the CF(3)-group rearrangement has been carried out to help establish the reaction mechanism of this uncommon transformation. Moreover, a route to trifluoromethyl-substituted iminosugars was also developed through the diastereoselective dihydroxylation of suitable s…
In vitro mammalian metabolism of the mitosis inhibitor zoxamide and the relationship to its in vitro toxicity.
2009
The in vitro mammalian metabolism of the fungicide zoxamide is related to its in vitro mammalian toxicity. After incubation of zoxamide with rat liver microsomes leading to practically 100% metabolism (mostly hydroxylated zoxamide), the cytotoxicity (methyl thiazole tetrazolium (MTT) test) and the mitosis-inhibiting potential (shown by cell count and by cell cycle analysis) for V79 were not distinguishable from those of zoxamide, demonstrating that the hydroxylation of zoxamide did not change the cytotoxicity or mitosis-inhibiting potential as determined by these assays. After incubation of zoxamide with rat liver S9 predominantly leading to conjugation with glutathione, and after incubatio…
Androgen hydroxylation catalysed by a cell line (SD1) that stably expresses rat hepatic cytochrome P-450 PB-4 (IIB1).
1989
Androgen hydroxylation catalysed by Chinese hamster fibroblast SD1 cells, which stably express cytochrome P-450 form PB-4, the rat P450IIB1 gene product, was assessed and compared to that catalysed by purified cytochrome P-450 PB-4 isolated from rat liver. SD1 cell homogenates catalysed the NADPH-dependent hydroxylation of androstenedione and testosterone with a regioselectivity very similar to that purified by P-450 PB-4 (16 beta-hydroxylation/16 alpha-hydroxylation = 6.0-6.8 for androstenedione; 16 beta/16 alpha = 0.9 for testosterone). Homogenates prepared from the parental cell line V79, which does not express detectable levels of P-450 PB-4 or any other cytochrome P-450, exhibited no a…
Modeling Tyrosinase and Catecholase Activity Using New m-Xylyl-Based Ligands with Bidentate Alkylamine Terminal Coordination
2012
Chemical model systems possessing the reactivity aspects of both tyrosinase and catechol oxidase are presented. Using two m-xylyl-based ligands providing bidentate alkylamine terminal coordination, 1,3-bis[(N,N-dimethylaminoethyl)aminomethyl]benzene (L(H,H)) and 1,3-bis[(N,N,N'-trimethylaminoethyl)aminomethyl]benzene (L(Me,Me)), four new dicopper(I) complexes, [Cu(I)(2)(L(H,H))(MeCN)(4)][ClO(4)](2) (1), [Cu(I)(2)(L(H,H))(PPh(3))(2)(MeCN)(2)][ClO(4)](2) (2), [Cu(I)(2)(L(Me,Me))(MeCN)(2)][ClO(4)](2) (3), and [Cu(I)(2)(L(Me,Me))(PPh(3))(2)][ClO(4)](2) (4), have been synthesized and characterized. Complex 2 has been structurally characterized. Reaction of the dicopper(I) complex 3(2+) with diox…
ChemInform Abstract: Tetramethylguanidine (TMG)-Catalyzed Addition of Dialkyl Phosphites to α,β-Unsaturated Carbonyl Compounds, Alkenenitriles, Aldeh…
2010
Abstract Tetramethylguanidine-catalyzed addition of dialkyl phosphites to α,β-unsaturated carbonyl compounds, alkenenitriles, aldehydes and ketones constitutes a practical route to a variety of phosphonate synthons. The very mild conditions employed, together with the short reaction times, make the procedure highly versatile and tolerant to a range of functionalities. The proposed methodology is also convenient for the preparation of α-aminophosphonates.
Selective Synthesis of New Fluorinated Alicyclic β-Amino Ester Stereoisomers (Eur. J. Org. Chem. 26/2011)
2011
The cover picture shows a waterfall located in the Eastern Carpathians in Transylvania, near Bicaz Canyon. Although fluorinated organic compounds are nonexistent in nature, an increasing number of drugs (25 %) on the market contain at least one fluorine atom. Cyclic fluorinated β-amino acid derivatives have been synthesized by selective hydroxylation and hydroxy?fluorine exchange. Details are discussed in the article by F. Fulop et al. on p. 4993 ff.