Search results for "Mixed Function Oxygenases"
showing 9 items of 49 documents
Evaluation of the genotoxic and cytochrome P450 monooxygenase‐inhibitory potential of dicuran on procaryotic and eucaryotic test systems
2000
The effect of the herbicide Dicuran 500 FL (formulated product) on the phenotypical and genotypical changes in procaryotic and eucaryotic organisms was investigated using short-term tests for detecting genotoxins. Since pesticides discharged in the water environment can modulate the mixed-function monooxygenases (MFO) detoxification system of water organisms, the in vivo and in vitro effects of Dicuran on hepatic cytochrome P450 (cyt P450) monooxygenase activities were also examined in juvenile carp (Cyprinus carpio L.). By measuring the activities of MFO in experimental carp exposed to Dicuran an attempt was made to establish whether Dicuran could be bioactivated by MFO into ultimate mutag…
Metabolites of diethylstilboestrol induce sister chromatid exchange in human cultured fibroblasts
1979
Diethylstilboesterol (DES) is one of the few substances for which a clear association with carcinogenicity has been established in man. Nevertheless, it is still widely used, mainly as a cheap oestrogen to increase the slaughter weight of beef, but in spite of this it is not known if residues in the meat or metabolites excreted by the cattle are hazardous to man. It is also unknown whether there is a threshold dose below which DES is harmless. A threshold might be expected if a hormonal mechanism of carcinogensis rather than metabolic activation to an electrophically reactive species operats. This possibility was supported by the observations that DES, in contrast to most other carcinogens,…
Membrane D-lactate oxidase in Zymomonas mobilis: evidence for a branched respiratory chain.
1998
Respiratory chain composition of the ethanol-producing bacterium Zymomonas mobilis was studied. Its membrane D-lactate oxidase was characterised. With NADH, but not D-lactate as substrate, a cytochrome o-like component was seen in CO difference spectra. Chlorpromazine specifically inhibited reduction of cytochrome d, while myxothiazol eliminated the cytochrome o-like features in CO difference spectra. It is suggested that electrons from NADH are distributed between branches terminated by the cytochrome o-like component, cytochrome a, and cytochrome d. With D-lactate, electrons are transported to cytochrome a, or an unidentified CN(-)-sensitive oxidase, and cytochrome d.
Effective hemostasis during minor surgery in a case of hereditary combined deficiency of vitamin K-dependent clotting factors.
2009
Combined deficiency of the vitamin K-dependent clotting factors (VKCFD) is a rare bleeding disorder involving defective gamma-carboxylation of coagulation factors II , VII, IX and X as well as natural anticoagulants protein C and protein S. The disease is characterized by a cluster of different, often life threatening, bleeding symptoms occurring both spontaneously and in a surgical setting. In the present paper we describe two different treatment modalities to be used both in a programmed surgical procedure and in an emergency scenario. As this disease is a natural model that resembles oral anticoagulation, our experience discloses a possible rationale in the use of recombinant activated …
A time-course investigation of vitamin A levels and drug metabolizing enzyme activities in rats following a single treatment with prototypic polychlo…
1987
Xenobiotics previously characterized as selective inducers of drug-metabolizing enzymes were chosen to probe possible relationships between enzyme induction and vitamin A metabolism. Liver, kidney and serum retinol and retinyl palmitate levels were investigated in male Sprague--Dawley rats receiving a single i.p. injection of the polychlorinated biphenyls (PCBs), 2,2',5,5'-tetrachlorobiphenyl, 3,3',4,4'-tetrachlorobiphenyl or 2,2',4,4',5,5'-hexachlorobiphenyl (300 mumol/kg) or 1,1,1-trichloro-2,2-bis-(4-chlorophenyl)-ethane (DDT) (150 mumol/kg). While 2,2',5,5'-tetrachlorobiphenyl, a weak or non-inducer, and 2,2',4,4',5,5'-hexaclorobiphenyl and DDT, phenobarbital-type inducers of cytochrome…
Magnaporthe oryzae as an expression host for the production of the unspecific peroxygenase AaeUPO from the basidiomycete Agrocybe aegerita.
2021
Abstract The filamentous fungus Magnaporthe oryzae has the potential to be developed as an alternative platform organism for the heterologous production of industrially important enzymes. M. oryzae is easy to handle, fast‐growing and unlike yeast, posttranslational modifications like N‐glycosylations are similar to the human organism. Here, we established M. oryzae as a host for the expression of the unspecific peroxygenase from the basidiomycete Agrocybe aegerita (AaeUPO). Note, UPOs are attractive biocatalysts for selective oxyfunctionalization of non‐activated carbon‐hydrogen bonds. To improve and simplify the isolation of AaeUPO in M. oryzae, we fused a Magnaporthe signal peptide for pr…
The induction of hepatic microsomal metabolism in rats following acute administration of a mixture of polybrominated biphenyls.
1976
Abstract Firemaster BP6, a mixture of polybrominated biphenyls (PBBs), was administered to female Sprague-Dawley rats (170–180 g) as a single ip injection at 25 and 150 mg/kg. Other animals received phenobarbital (PB), 3-methylcholanthrene (3MC), or PB and 3MC together. Animals were killed at intervals of 12, 24, 48, 192, and 336 hr after treatment with PBBs, or 24 hr after PB, MC, or PB-MC, and various hepatic microsomal parameters were measured. After 150 mg/kg of PBBs, cytochrome P450 concentrations reached a maximum by 48 hr (225% of control), then remained elevated through 336 hr. A similar pattern of induction was observed for epoxide hydratase and aniline hydroxylase activities. In c…
Regulation of cytochrome P450 IID by acute phase mediators in C3H/HeJ mice.
1992
Abstract Cytochrome P450 IID6 is a drug metabolizing enzyme and the major target antigen in LKM-1 antibody positive chronic active hepatitis. The histological hallmark of chronic active hepatitis is a lymphocytic infiltrate in the liver. It is unknown whether and how cytokines produced and secreted by these tissue infiltrating mononuclear cells regulate the cellular expression of cytochrome P450 IID6. To study the effect of interleukin 1, tumor necrosis factor and interleukin 6 on the hepatocellular RNA expression of cytochrome P450 IID, we injected each of the cytokines in C3H HeJ mice. We found a time-dependent suppression of the cytochrome in the liver. Six hours after the intraperitonea…
Production and characterization of the recombinant Sphingomonas chlorophenolica pentachlorophenol 4-monooxygenase.
2001
Abstract Pentachlorophenol 4-monooxygenase (PCP4MO) from Sphingomonas chlorophenolica is a flavoprotein that hydroxylates PCP in the presence of NADPH and oxygen. In order to investigate the structure and function of active site, recombinant PCP4MO (rePCP4MO) was produced in Escherichia coli as a glutathione S-transferase (GST) fusion protein. Moreover, a tobacco etch virus (TEV) protease cleavage site (EKLYFQG) was introduced into GST-PCP4MO and a his-tagged TEV protease was employed. Hence, a two-step purification protocol was developed which allowed obtaining 15–20 mg of rePCP4MO from 1 L culture. The rePCP4MO revealed identity with native enzyme by SDS–PAGE and N-terminal sequence analy…