scholarly journals Fatty acid requirements and temperature dependence of monooxygenase activity in rat liver microsomes

1978 ◽  
Vol 512 (1) ◽  
pp. 136-146 ◽  
Author(s):  
Joseph F. Becker ◽  
Thomas Meehan ◽  
James C. Bartholomew
Keyword(s):  
Fatty Acid ◽  
Temperature Dependence ◽  
Rat Liver ◽  
Liver Microsomes ◽  
Rat Liver Microsomes ◽  
Monooxygenase Activity

Inhibitory effect of curcumin on fatty acid desaturation inMortierella alpina 1S-4 and rat liver microsomes

Lipids ◽  
1992 ◽  
Vol 27 (7) ◽  
pp. 509-512 ◽  
Author(s):  
Sakayu Shimizu ◽  
Saeree Jareonkitmongkol ◽  
Hiroshi Kawashima ◽  
Kengo Akimoto ◽  
Hideaki Yamada
Keyword(s):  
Fatty Acid ◽  
Rat Liver ◽  
Liver Microsomes ◽  
Inhibitory Effect ◽  
Fatty Acid Desaturation ◽  
Rat Liver Microsomes

Fluorescence polarization studies of rat liver microsomes with altered phospholipid desaturase activities

1980 ◽  
Vol 58 (10) ◽  
pp. 952-958 ◽  
Author(s):  
E. L. Pugh ◽  
M. Kates ◽  
A. G. Szabo
Keyword(s):  
Fatty Acid ◽  
Rat Liver ◽  
Fluorescence Polarization ◽  
Desaturase Activity ◽  
Liver Microsomes ◽  
Rat Liver Microsomes ◽  
Polarization Ratio ◽  
Parinaric Acid ◽  
Cis And Trans ◽  
Normal Controls

Phospholipid desaturase activity of rat liver microsomes can be varied by dietary manipulation: rats starved and refed a "fat-free" diet have two to three times the activity of normal controls whereas starved rats have no detectable activity. These changes were accompanied by changes in fatty acid composition of the microsomal phospholipids, resulting in a double bond:saturated fatty acid mole ratio (moles double bonds per mole saturated fatty acid) of 5.7 in control and starved rats and 4.7 in starved–refed rats. Fluorescence polarization ratio [Formula: see text] of cis- and trans-parinaric acid (PnA) showed no significant differences in physical state of the three microsomal preparations. However, the isolated microsomal phospholipids with trans-PnA as probe showed differences in the temperature at which onset of a change in polarization ratio occurred (starved–refed > normal > starved rats). With the cis-PnA as probe, the polarization ratio showed no change in the range 10–40 °C but was significantly higher (1.8) in starved–refed rats than in normal and starved rats (1.6 in both cases). These data indicate that the microsomal phospholipids of starved–refed animals were in a less fluid state than those from control and starved rats and that this decrease in fluidity was correlated with an increase in phospholipid desaturase activity.

scholarly journals Nicardipine and Nifedipine Inhibit Fatty Acid Desaturases in Rat Liver Microsomes

1996 ◽  
Vol 60 (10) ◽  
pp. 1672-1676 ◽  
Author(s):  
Hiroshi Kawashima ◽  
Kengo Akimoto ◽  
Saeree Jareonkitmongkol ◽  
Norifumi Shirasaka ◽  
Sakayu Shimizu
Keyword(s):  
Fatty Acid ◽  
Rat Liver ◽  
Liver Microsomes ◽  
Rat Liver Microsomes ◽  
Fatty Acid Desaturases

Biosynthetic utilization of photoreactive fatty acids by rat liver microsomes

1984 ◽  
Vol 62 (6) ◽  
pp. 375-378 ◽  
Author(s):  
Pierre Leblanc ◽  
Gerhard E. Gerber
Keyword(s):  
Fatty Acids ◽  
Fatty Acid ◽  
Rat Liver ◽  
Alkyl Chain ◽  
Liver Microsomes ◽  
Rat Liver Microsomes ◽  
Phospholipid Synthesis ◽  
Derivatives Of

The photoreactive ω-diazirinophenoxy derivatives of nonanoate, undecanoate, tridecanoate, and pentadecanoate were shown to be activated by rat liver microsomes to the corresponding acyl-CoA derivatives. The Km and Vmax for these fatty acid analogues were determined; the values obtained indicate that the addition of a photoreactive group to an alkyl chain has an effect similar to that of elongation of the chain by about seven carbons. Incubation of microsomes in the presence of lysophospholipids resulted in the incorporation of the photoreactive fatty acids into the corresponding phospholipids. The ability of mammalian systems to utilize these photoreactive fatty acids for phospholipid synthesis establishes their suitability as photoaffinity analogues of fatty acids.

A Direct, Highly Sensitive Fluorometric Assay for a Microsomal Cytochrome P450-Mediated O-Demethylation Using a Novel Coumarin Analog as Substrate

2000 ◽  
Vol 55 (11-12) ◽  
pp. 915-922 ◽  
Author(s):  
René Roser ◽  
Helmut Thomas
Keyword(s):  
Rat Liver ◽  
Liver Microsomes ◽  
Fluorometric Assay ◽  
Excitation Wavelength ◽  
Monooxygenase System ◽  
Rat Liver Microsomes ◽  
Monooxygenase Activity ◽  
Continuous Increase ◽  
Highly Sensitive

A highly sensitive fluorometric assay for the determination of monooxygenase activity in liver microsomes is described. The assay is based on the use of 3-chloro-7-methoxy-4-methylcoumarin which is demethylated to 3-chloro-7-hydroxy-4-methylcoumarin. The rate of formation of 3-chloro-7-hydroxy-4-methylcoumarin was recorded as an increase of fluorescence (λA = 380 nm, λF = 480 nm ) with time. When 3-chloro-7-methoxy-4-methylcoumarin was incubated in the presence of MgCl2and NADPH with rat liver microsomes, a continuous increase of the fluorescence could be measured. The reaction proceeded linearly for about 10 min and at least up to a concentration of 0.1 mg/ml of microsomal protein. Besides 3-chloro-7-hydroxy-4-methylcoumarin a hydroxylated derivative of the substrate was formed as a second metabolite during the incubation. Using an excitation wavelength of 480 nm and a fluorescence/em ission w avelength of 480 nm, the fluorescence of this substance (λA = 338 nm, λF = 422 nm ) amounted only to about 1% of the fluorescence of the main product. The use of 3-chloro-7-methoxy-4-methylcoumarin as substrate enables the fluorometric determination of the O-dealkylation activity of a cytochrom e P450-dependent monooxygenase system in rat liver which is inducible by phenobarbital but not by 3-methylcholanthrene.

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