Disease relevance of C11052

• The activity of 7-ethoxycoumarin 0-deethylase and associated NADPH-cytochrome c reductase was determined in 9000 g supernatant from bioptically obtained liver specimens from patients with various liver diseases in order to study in vitro drug metabolising capacity [1].
• Cutaneous xenobiotic metabolizing enzymes including aryl hydrocarbon hydroxylase (AHH), 7-ethoxycoumarin O-deethylase (ECD), epoxide hydrolase (EH) and glutathione S-transferase (GST) activities were examined in SKH hairless mice chronically irradiated with UVB to induce squamous cell carcinoma (SCC) [2].
• A recombinant strain of E. coli was able to mediate the O dealkylation of 7-ethoxycoumarin in good yield, despite the absence of any recombinant redox proteins [3].
• Activities of the microsomal mono-oxygenases 7-ethoxycoumarin O-de-ethylase (EOC) and aldrin epoxidase (AE), together with microsomal epoxide hydrolase (EH) activity and concentrations of reduced glutathione (GSH) have been measured in liver from patients with alcoholic cirrhosis and in normals [4].
• The metabolism of 7-ethoxycoumarin in human liver microsomes and the effect of primary biliary cirrhosis: implications for studies of drug metabolism in liver disease [5].

High impact information on C11052

• In vitro studies with human liver microsomes showed that omeprazole in equimolar concentrations (0.5 mM) was a stronger inhibitor than cimetidine of 7-ethoxycoumarin deethylase activity [6].
• Topical application of benz(a)anthracene to mouse skin elicited a 2-fold increase in cytochrome P-450 content, with accompanying increases in monooxygenase activities such as benzo(a)pyrene hydroxylation, 7-ethoxycoumarin O-deethylation, and acetanilide 4-hydroxylation, in the microsomes [7].
• The purified preparation efficiently catalyzed benzo(a)pyrene hydroxylation and 7-ethoxycoumarin O-deethylation when reconstituted with NADPH-cytochrome P-450 reductase [7].
• 7-Ethoxycoumarin deethylase activity, a cytochrome P-450-dependent pathway, was low or undetectable in the three cell fractions [8].
• We prepared a monoclonal antibody (MAb 1-7-1) to a polycyclic hydrocarbon-induced rat cytochrome P-450 that antigenically defines and inhibits a type of cytochrome P-450 responsible for aryl hydrocarbon hydroxylase (AHH) and 7-ethoxycoumarin deethylase (ECD) activity in human placenta [9].

Chemical compound and disease context of C11052

• Our data suggest that antipyrine elimination is not related to 7-ethoxycoumarin O-deethylase activity in liver disease [10].
• Measurement of 7-ethoxycoumarin O-deethylase and benzphetamine N-demethylase activities indicated that the loss of protection by HCB or TCB against benzene toxicity after 7 days was not associated with changes in the activities of hepatic mixed-function oxidases inducible by 3-methylcholanthrene or phenobarbital [11].

Biological context of C11052

• Studies of inhibitors of 7-ethoxycoumarin O-deethylation and aryl hydrocarbon hydroxylation in homogenates of Zymbal's glands from beta-naphthoflavone-treated rats suggest that these enzyme activities are catalyzed by cytochrome P-450 [12].
• This dramatic decrease in the C-H bond cleavage rate does not, however, alter the rate of 7-ethoxycoumarin disappearance or the rates of NADPH and oxygen consumption indicating that the catalytic turnover of this enzyme is unaffected [13].
• Interactions between glycolysis and mixed function oxidation: studies with 7-ethoxycoumarin in perfused livers from beta-naphthoflavone-treated rats [14].
• Preinfusion with KCN, an inhibitor of oxidative phosphorylation, caused the rate of 7-ethoxycoumarin O-deethylation to decline by 60% over 30 min of perfusion [14].
• The IC50 of Fadrozole was 33 nM for aromatase and 67 nM for 7-ethoxycoumarin O-deethylase [15].

Anatomical context of C11052

• There are only minimal activities that can be found in substantial quantities in placentas without maternal smoking; one example is 7-ethoxycoumarin O-deethylase (ECOD) [16].
• PICM-19 P-450 activity induced by 7-ethoxycoumarin was nearly equivalent to that of primary cultures of pig hepatocytes [17].
• These data indicate that mitochondria supply 50 to 70% of the reducing equivalents for mixed function oxidation of 7-ethoxycoumarin in both regions of the liver lobule in livers from fed rats [18].
• To investigate the drug-metabolizing potential of different sub-populations of cells along the villus-crypt surface of the small intestine, the major monooxygenase activities directed towards the substrates benzo[a]pyrene (BP), 7-ethoxycoumarin and ethylmorphine were studied [19].
• The activities of aryl hydrocarbon hydroxylase and 7-ethoxycoumarin O-de-ethylase in the rat submandibular gland, both of which are normally very low, were increased about 10- and 25-fold, respectively, by administration of 3-methylcholanthrene [20].

Associations of C11052 with other chemical compounds

• In pulmonary microsomes, the N-demethylation of benzphetamine, amino-pyrine, and ethylmorphine, and the O-deethylation of 7-ethoxycoumarin are dependent only on cytochrome P-450I, and the hydroxylation of coumarin is apparently catalyzed by both cytochromes [21].
• Unlike other cytochromes P-450 isolated from rat liver microsomes, the enzyme showed no activity toward testosterone and xenobiotics such as 7-ethoxycoumarin and benzo[a] pyrene [22].
• With V114I, hydroxylation of steroids and warfarin and 2-hydroxylation of 245-HCB were decreased, whereas 7-ethoxycoumarin O-dealkylation and 3-hydroxylation of 245-HCB were unaltered [23].
• Malate, which is a substrate for the malic enzyme shuttle mechanism involved in the transfer of reducing equivalents from the mitochondria to the cytosol, increased 10-fold during infusion of 7-ethoxycoumarin in livers from beta-naphthoflavone-treated rats but less than 3-fold in livers from control rats [24].
• In fact other powerful scavengers of oxygen radicals like dimethylthiourea, desferal, and catalase itself maintain higher levels of cytochrome P450 and higher activities of 7-ethoxycoumarin O-deethylase during 3 days of culture [25].

Gene context of C11052

• The degree of inhibition defines the contribution of CYP2A6 activity to the 4-nitroanisole and 7-ethoxycoumarin metabolism in human liver and the range reflects the variability among samples [26].
• The catalytic activities of 7-ethoxycoumarin O-deethylase (ECOD), 7-ethoxyresorufin O-deethylase (EROD) and aryl hydrocarbon hydroxylase (AHH) were substantially increased in response to maternal cigarette smoking, and paralleled the amount of CYP1A1 mRNA and protein [27].
• Assay of 7-ethoxycoumarin O-deethylase activity demonstrated that ER-181 cells acquired the catalytic function of CYP2E1 [28].
• CYP1B1 did not oxidize other typical P450 substrates such as coumarin, tolbutamide, S-mephenytoin, chlorzoxazone, nifedipine, and testosterone, while low rates of oxidation of bufuralol and 7-ethoxycoumarin were found for CYP1B1 [29].
• With these kinetic parameters (excluding CYP1A1) we found that CYP1A2 and 2E1 were the major enzymes catalyzing 7-ethoxycoumarin; the contributions of these two forms were dependent on the contents of these CYPs in liver microsomes of different humans [30].

Analytical, diagnostic and therapeutic context of C11052

• Livers from fasted beta-naphthoflavone-treated rats were employed because rates of 7-ethoxycoumarin O-deethylation were constant (16 mumol/g/hr) for at least 1 hr of perfusion [14].
• Molecular cloning and functional expression in yeast of CYP76B1, a xenobiotic-inducible 7-ethoxycoumarin O-de-ethylase from Helianthus tuberosus [31].
• 2. The interaction of a series of suicide substrates of cytochrome P-450 with the hepatic and olfactory mono-oxygenase systems has been assessed by determination of peroxidase, 7-ethoxycoumarin O-de-ethylase (ECOD) and 7-ethoxyresorufin O-de-ethylase (EROD) activities after treatment in vivo with these compounds [32].
• Site-directed mutageneses of rat liver cytochrome P-450d: catalytic activities toward benzphetamine and 7-ethoxycoumarin [33].
• The 7-ethoxycoumarin O-deethylase,p-nitrophenol hydroxylase, and N-nitrosodimethylamine (NDMA) demethylase activities of the P450 in these cells were measured in monolayer cell cultures without preparing microsomes [34].

References