scholarly journals Metabolism of 4-n-Nonylphenol by Non-modified and CYP1A1- and CYP1A2-Transgenic Cell Cultures of Tobacco

2005 ◽  
Vol 60 (11-12) ◽  
pp. 883-892 ◽  
Author(s):  
Angelika Berger ◽  
Alexander S. Ruß ◽  
Ingolf Schuphan ◽  
Burkhard Schmidt
Keyword(s):  
Cell Suspension Cultures ◽  
Oxidative Capacity ◽  
Side Chain ◽  
Phase System ◽  
Metabolic Profiles ◽  
Hydrolytic Cleavage ◽  
Primary Metabolites ◽  
Glycosidic Cleavage ◽  
Transgenic Cell ◽  
Human Cytochrome

The metabolism of 14C-4-n-nonylphenol (14C-4-n-NP), as a mo-el for the xenoestrogen nonylphenol, was investigate- in three types of tobacco cell suspension cultures: one genetically non-modified culture (NT) and two cultures constitutively expressing human cytochrome P450 CYP1A1 or CYP1A2. With 1 mg l-1 of 14C-4-n-NP and 24 h of incubation, the xenobiotic was transformed almost completely to glycosides. After glycosidic cleavage, 14C-4-n-NP and several primary metabolites of 14C-4-n-NP were liberated. Portions of the primary metabolites were 29.3% (NT culture), 34.3% (CYP1A1 culture), and 50.7% of applied 14C(CYP1A2 culture). Thus, the endogenous capacity of the tobacco cells to form primary metabolites of 4-n-NP was noticeably higher than that of CYP1A1 or CYP1A2. The results however clearly suggest that 4-n-NP is - even though a poor - substrate of CYP1A1 an- CYP1A2. In order to examine metabolic profiles of 4-n-NP in the NT, CYP1A1 and CYP1A2 cultures, the suspensions were exposed to 10 mg l-1 of 14C-4-n-NP using a two-liquid-phase system with carrier n-hexadecane and 192 h of incubation. Results obtained resembled those of the low concentration study. The oxidative metabolic profiles determined after hydrolytic cleavage using GC-EIMS were similar in the NT, CYP1A1 and CYP1A2 cultures. Main metabolites were side-chain mono-hydroxylated derivatives of 4-n-NP with 6′-, 7′- and 8′- OH-4-n-NP as prominent metabolites. In addition, olefinic side-chain hydroxy, ring methoxylated, keto and ring hydroxylated derivatives were observed. The lack of differences in metabolic profiles among the CYP1A1, CYP1A2 and NT cultures was referred to the low enzymatic activity of CYP1A1 and CYP1A2 as compared to the higher endogenous oxidative capacity of tobacco, as well as to similar metabolic profiles of 4-n-NP produced by CYP1A1 and CYP1A2 an- tobacco itself.

scholarly journals Wasserlösliche Phosphane, III [1]. Wasserlösliche primäre Phosphane mit Ammoniumgruppierungen NR2R' in der Seitenkette -donorfunktionalisierte Amphiphile / Water-Soluble Phosphanes, III [1]. Water-Soluble Primary Phosphanes with Ammonium Groups NR2R' in the Side Chain -Donor-Functionalized Amphiphiles

1994 ◽  
Vol 49 (11) ◽  
pp. 1511-1524 ◽  
Author(s):  
David J. Brauer ◽  
Jörg Fischer ◽  
Stefan Kucken ◽  
Klaus P. Langhans ◽  
Othmar Stelzer ◽  
...  
Keyword(s):  
Water Solubility ◽  
Water Soluble ◽  
Side Chain ◽  
Phase System ◽  
Alkyl Side Chain ◽  
Two Phase ◽  
Trans Conformation ◽  
Phosphonous Acid ◽  
X Ray ◽  
Superbasic Medium

Primary and secondary aminoalkylphosphanes R2N-(CH2)m-PH2 (R2 = Me2, nBu2, C5H10, C4H8O, 2-(1-Methyl-2-pyrrolidinyl); m = 2, 3, 6, 10, 11; 1-6) or [R2N-(CH2)m]2PH (7, R2 = C5H10; m = 2) are accessible by aminoalkylation of PH3 with ω̃ -chloroalkylamines R2N-(CH2)m-Cl in the superbasic medium DMSO/KOH (DMSO = dimethylsulfoxide). By selective N-quaternization of 1, 2, 4-6 with R'I (R' = Me, CnH2n+1; n = 6-8, 12, 16, 18) in the two-phase system CH2Cl2/H2O novel primary phosphanes [R'R2N-(CH2)m-PH2]+I- (11-16f) with quaternary ammonium groups in the alkyl side chain are obtained. The water solubility of 11-16f decreases with increasing chain length (n) of R′ 11 (R = R' = Me; m = 2) shows a trans conformation at the C2H4 bridge according to an X-ray structural analysis. Protonation of 1, 2, 4, 5 with HCl affords the water-soluble hydrochlorides [HR2N-(CH2)m-PH2]+Cl- (19-22). The cationic primary phosphanes 11-16f are stable towards oxygen. By oxidation of 11 with one or two equivalents of H2O2 the primary phosphane oxide [Me3N-(CH2)2-P(O)H2]+I- (23) or the phosphonous acid [Me3N-(CH2)2- P(O)(OH)H]+I- (23a) are formed. Hofmann degradation of 11 or 16c with KOH yields phosphirane in good yields. Reaction of 1, 2, 4-6 (L) with Fe2(CO)9 at ambient temperature yields stable complexes (CO)4FeL (26-30). Under more rigorous conditions Fe3 clusters (31, 32) with free R2N groups are obtained.

Metabolic Fingerprinting and Profiling of Arabidopsis thaliana Leaf and its Cultured Cells T87 by GC/MS

2006 ◽  
Vol 61 (3-4) ◽  
pp. 267-272 ◽  
Author(s):  
Eiichiro Fukusaki ◽  
Kanokwan Jumtee ◽  
Takeshi Bamba ◽  
Takehiro Yamaji ◽  
Akio Kobayashi
Keyword(s):  
Arabidopsis Thaliana ◽  
Cell Suspension ◽  
Cultured Cells ◽  
Cell Suspension Cultures ◽  
Metabolite Profile ◽  
Culture Cell ◽  
Suspension Cultures ◽  
Primary Metabolite ◽  
Primary Metabolites ◽  
Suspension Culture Cell

Cell suspension cultures are now recognized as important model materials for plant bioscience and biotechnology. Very few studies of metabolic comparisons between cell cultures and original plants have been reported, even though the biological identity of cultured cells with the normally grown plant is of great importance. In this study, a comparison of the metabolome for primary metabolites extracted from the leaves of Arabidopsis thaliana and cultured cells from an Arabidopsis suspension culture (cell line T87) was performed. The results suggest that although cell suspension cultures and Arabidopsis leaves showed similarities in the common primary metabolite profile, nonetheless, moderate differences in quantitative profile were revealed.

Carbon-Carbon Bond Cleavage Catalyzed by Human Cytochrome P450 Enzymes: a-Ketol as the Key Intermediate Metabolite in Sequential Metabolism of Olanexidine

2019 ◽  
Vol 13 ◽  
Author(s):  
Yiding Hu ◽  
Yi Xiao ◽  
Zhesui Rao ◽  
Vasant Kumar ◽  
Hanlan Liu ◽  
...  
Keyword(s):  
Cytochrome P450 ◽  
Bond Cleavage ◽  
Liver Microsomes ◽  
Side Chain ◽  
Cytochrome P450 Enzymes ◽  
Acid Metabolite ◽  
Carbon Bond ◽  
Carbon Carbon Bond ◽  
Human Cytochrome

Background: Carbon-carbon bond cleavage of a saturated aliphatic moiety is rarely seen in xenobiotic metabolism. Olanexidine (Olanedine®), containing an n-octyl (C8) side chain, was mainly metabolized to various shortened side chain (C4 to C6) acid-containing metabolites in vivo in preclinical species. In liver microsomes and S9, the major metabolites of olanexidine were from multi-oxidation on its n-octyl (C8) side chain. However, the carbon-carbon bond cleavage mechanism of n-octyl (C8) side chain, and enzyme(s) responsible for its metabolism in human remained unknown. Methods: A pair of regioisomers of -ketol-containing C8 side chain olanexidine analogs (3,2-ketol olanexidine and 2,3-ketol olanexidine) were synthesized, followed by incubation in human liver microsomes, recombinant human cytochrome P450 enzymes or human hepatocytes, and subsequent metabolite identification using LC/UV/MS. Results: Multiple shortened side chain (C4 to C6) metabolites were identified, including C4, C5 and C6-acid and C6-hydroxyl metabolites. Among 19 cytochrome P450 enzymes tested, CYP2D6, CYP3A4 and CYP3A5 were identified to catalyze carbon-carbon bond cleavage. Conclusions: 3,2-ketol olanexidine and 2,3-ketol olanexidine were confirmed as the key intermediates in carbon-carbon bond cleavage. Its mechanism is proposed that a nucleophilic addition of iron-peroxo species, generated by CYP2D6 and CYP3A4/5, to the carbonyl group caused the carbon-carbon bond cleavage between the adjacent hydroxyl and ketone groups. As results, 2,3-ketol olanexidine formed a C6 side chain acid metabolite. While, 3,2-ketol olanexidine formed a C6 side chain aldehyde intermediate, which was either oxidized to a C6 side chain acid metabolite or reduced to a C6 side chain hydroxyl metabolite.

Increasing anthraquinone production by overexpression of 1-deoxy-d-xylulose-5-phosphate synthase in transgenic cell suspension cultures of Morinda citrifolia

2010 ◽  
Vol 32 (7) ◽  
pp. 997-1003 ◽  
Author(s):  
Carla Quevedo ◽  
María Perassolo ◽  
Eugenia Alechine ◽  
Daniel Corach ◽  
Ana María Giulietti ◽  
...  
Keyword(s):  
Cell Suspension ◽  
Cell Suspension Cultures ◽  
Suspension Cultures ◽  
Morinda Citrifolia ◽  
Transgenic Cell ◽  
Phosphate Synthase

scholarly journals Steric effects on the rate of hydrolysis by palladium(II) complexes of the C-terminal amide bond in a series of methionine-containing dipeptides AcMet-Aa

2004 ◽  
Vol 69 (11) ◽  
pp. 887-899 ◽  
Author(s):  
Wade Johnson ◽  
Nenad Kostic
Keyword(s):  
Amino Acid ◽  
Rate Constant ◽  
Amide Bond ◽  
Side Chain ◽  
Detectable Effect ◽  
Hydrolytic Cleavage ◽  
Bidentate Ligands ◽  
Branching Patterns ◽  
Rate Of Hydrolysis ◽  
Leaving Groups

A series of N-acetylated, methionine-containing dipeptides designated AcMet-Aa containing various C-terminal amino acids designated Aa are hydrolyzed in aqueous solution at 50 ?C and 0.95 < pD < 1.10 in the presence of three cis-[Pd(L)(H2O)2]2+ complexes, in which L are bidentate ligands en Me4en, and 3-OH-dtco. The reactions were monitored by 1H-NMR spectroscopy. The rate constant for hydrolytic cleavage of the Met-Aa bond decreases as the steric bulk of the amino acid Aa increases. Correlations to Taft?s Es values were made. The substituents on ?-C and ?-C atoms lower the rate constant most, those on the ?-C atom lower it less, and those on the ?-C have no detectable effect. Partial selectivity for leaving amino acid Aa is attributed to differences in the volume of the side chain and to discrimination between leaving groups of similar volume but different branching patterns.

scholarly journals Phe120 contributes to the regiospecificity of cytochrome P450 2D6: mutation leads to the formation of a novel dextromethorphan metabolite

2004 ◽  
Vol 380 (2) ◽  
pp. 353-360 ◽  
Author(s):  
Jack U. FLANAGAN ◽  
Jean-Didier MARÉCHAL ◽  
Richard WARD ◽  
Carol A. KEMP ◽  
Lesley A. McLAUGHLIN ◽  
...  
Keyword(s):  
Cytochrome P450 ◽  
Active Site ◽  
Structural Model ◽  
Side Chain ◽  
Cytochrome P450 2D6 ◽  
Active Site Residues ◽  
Bacterial Membranes ◽  
Human Cytochrome ◽  
Methionine Residues ◽  
P450 2D6

Although the residues that determine the preference of CYP2D6 (cytochrome P450 2D6) for compounds containing a basic nitrogen are well characterized, the contribution of other active site residues to substrate binding and orientation is less well understood. Our structural model of CYP2D6 identifies the aromatic residue Phe120 as a likely major feature of the active site. To examine the role of Phe120, mutants of CYP2D6 in which this residue has been substituted by alanine, leucine, tyrosine, serine, histidine, tryptophan or methionine residues have been prepared in bacterial membranes co-expressing human cytochrome NADPH cytochrome P450 oxidoreductase. The mutants have been characterized using the prototypical bufuralol 1´ hydroxylase and dextromethorphan O- and N-demethylase activities of CYP2D6. Larger effects on Km values are observed for dextromethorphan O-demethylation than for bufuralol 1´ hydroxylation, indicating that the Phe120 side chain is more important in dextromethorphan than in bufuralol binding. A role for this side chain in determining the regiospecificity of substrate oxidation was indicated by changes in the relative rates of O- and N-demethylation of dextromethorphan and, notably, by the formation of 7-hydroxy dextromethrophan, a novel dextromethorphan metabolite, in mutants in which it had been substituted. Computational studies of dextromethorphan binding to the active site of the Phe120→Ala mutant were carried out to throw light on the way in which the removal of this side chain leads to different modes of ligand binding.

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