Debey, Pascale Land, Edward J. Santus, Rene Swallow, A.John
Published in
Biochemical and Biophysical Research Communications
Several rate constants for one-electron reduction of cytochrome P450 are more rapid in the absence than in the presence of the specific substrate. The respective values for methyl viologen, nicotinamide adenine dinucleotide and the 1-methyl-4-(and -3-)carbamidopyridinium radicals are 2.6, 3.4, 6 and 35 × 10 7 M −1 s −1 without camphor, and 0.15, 0....
Kido, Toshiko Yamakura, Fumiyuki Kimura, Tokuji
Published in
Biochimica et Biophysica Acta (BBA)/Lipids and Lipid Metabolism
We have studied the cholesterol-binding reaction with purified steroid-free cytochrome P-450 scc . By mixing an aqueous solution of cholesterol-, pregnenolone- and progesterone-free cytochrome with cholesterol-containing liposomes, the low to high spin conversion of the hemoprotein was observed spectrophotometrically and by electron spin resonance ...
Burke, M.Danny Falzon, Miriam Milton, Anthony S.
Published in
Biochemical Pharmacology
Indomethacin administration to rats caused a dose-dependent decrease in hepatic microsomal cytochrome P450, aminopyrine N-demethylase, ethoxyresorufin O-de-ethylase and benzyloxyresorufin O-debenzylase, accompanied by selective alterations in microsomal sodium dodecylsulphate polyacrylamide gel electrophoretograms. High doses (⪖8.5 mg/kg) caused th...
Mole, M.Leonard Sanders, Linda Oglesby, Linda A.
Published in
Analytical Biochemistry
A high-performance liquid chromatographic method has been modified for the evaluation of both Phase I and II metabolism of biphenyl by hepatocytes maintained in an embryo/hepatocyte co-culture medium. Extracts of the media, before and after hydrolysis of conjugates, are directly injected onto the HPLC and the major hydroxylated metabolites plus unm...
Snowdowne, Kenneth W. Rosenoer, Leonie Yu, Ellen Cashman, John R.
Published in
Biochemical and Biophysical Research Communications
The effects of various eicosanoids on cytoplasmic calcium and the release of amylase were examined in isolated rat parotid cells. Arachidonate and several of its metabolites increased amylase release and elevated cytoplasmic calcium. Melittin, a stimulator of arachidonate mobilization, and lyso-phosphatidylcholine also released amylase and elevated...
Sesardic, Dorothea Cole, Kathleen J. Edwards, Robert J. Davies, Donald S. Thomas, Paul E. Levin, Wayne Boobis, Alan R.
Published in
Biochemical Pharmacology
The metabolism of phenacetin is primarily by cytochrome P450-dependent O-deethylation to paracetamol (POD activity). In untreated rats, microsomal POD activity is detectable in both the liver and lung, but not in the small intestine or the kidney. POD activity is highly induced in both hepatic and extrahepatic tissues of the rat following treatment...
Riddick, David S. Marks, Gerald S.
Published in
Biochemical Pharmacology
The porphyrinogenicity of 4-alkyl analogues of 3,5-diethoxycarbonyl-1,4-dihydro-2,4,6-tri-methylpyridine (DDC) is related to the process of mechanism-based destruction of cytochrome P450 (P450) heme, accompanied by conversion of heme to N-alkylprotoporphyrins ( N-alkylPPs). Certain DDC analogues (4-isopropyl, 4-isobutyl, 4-hexyl) are weakly porphyr...
Sesardic, Dorothea Edwards, Robert J. Davies, Donald S. Thomas, Paul E. Levin, Wayne Boobis, Alan R.
Published in
Biochemical Pharmacology
Phenacetin is metabolized primarily by O-deethylation to paracetamol (POD activity), a reaction catalysed by cytochrome P450. The high affinity component of POD activity is inducible in rat liver by treatment of the animals with polycyclic aromatic hydrocarbons. Following treatment with hydrocarbons such as 3-methylcholanthrene (MC) and isosafrole ...
Chasserot-Golaz, Sylvette Beck, Gisèle Venetianer, Aniko Corcos, Laurent
Published in
Biochemical Pharmacology
Phenobarbital is a potent inducer of several liver-specific genes such as those encoding detoxication enzymes, including cytochromes P450. However, the mechanisms of action of the barbiturate are poorly understood. Since both, phenobarbital and glucocorticoids, are capable of inducing the same cytochrome P450 species, we asked whether the glucocort...
Raucy, Judy L. Carpenter, Susan J. Trzaskos, James M.
Published in
Biochemical and Biophysical Research Communications
Lanosterol 14α-methyl demethylase was investigated in human tissues using a radio-HPLC assay to detect the 4,4-dimethyl-5α-cholesta-8,14-dien-3β-ol (diene) metabolite. The sequence of events leading to the demethylated product in human liver microsomes involves the conversion of the diol to the aldehyde followed by diene formation. Enzyme activity ...
