Liver microsomal protein

Ruangyuttikam, W. Skiles, G. L. Yost, G. S. Identification of a cysteinyl adduct of oxidized 3-methylindole from goat lung and human liver microsomal proteins. Chem. Res. Toxicol. 1992, 5, 713-719. 

Figure 3. Effect of temperature on conversion of molinate to its sulfoxide by carp liver microsomal mfo (liver microsomal protein 6 mg/mL, pH 7.4, NADPH 3 mg incubated for 15 min)...

Figure 4. Effect of carp liver microsomal protein concentration on its mfo activity (NADPH 3 mg/mL, pH 7.4 incubated for 15 min at 25°C)...

Figure 9.128 Typical chromatogram of the metabolites of testosterone formed by 1.0 mg of liver microsomal protein in 1.0 mL of reaction mixture incubated for 10 minutes at 37°C with (upper trace) and without (lower trace) a source of NADPH. (From van der Hoeven, 1984.)...

The second alternative function of PDI again comes from sequence analysis. This time a clone isolated as a lodothyronine 5 -monodeiodinase (5 -MD, thyroxine deiodinase) from rat codes for a protein that is identical to PDI in all but two residues (Boado et ai, 1988). The clone was isolated by screening a library with polyclonal antibodies raised against rat liver microsomal proteins. Clones coding for 5 -MD were selected by... 

Significant differences in the equilibrium constants for carbon monoxide binding to cytochromes P450 from bacterial, liver microsomal, and adrenal cortex microsomal sources, different isozymes of the liver microsomal proteins, and for substrate-free and substrate-bound enzymes, have been observed and have been related to similar factors that affect O2 and CO binding in oxygen transport and storage heme proteins. The importance of the cis and tmns effects, that is electronic effects associated with the porphyrin... 

Groups of normal and vitamin C deficient guinea pigs (21 d) were given 50 mg of ascorbic acid in their drinking water for 3, 6, and 10 a. Enzyme activity measured as fimol of product formedjh1100 mg of liver microsomal protein at 27° C. Key activity in normal animals, cross-hatched bar activity in vitamin C deficient animals, open bar vitamin C deficient animals given supplements of ascorbic acid for days indicated, solid bar. 

Y Masubuchi, J Araki, S Narimatsa, I Suzuki. Metabolic activation of lidocaine and covalent binding to rat liver microsomal protein. Biochem Pharmacol 43(12) 2551, 1992. 

The CoA-fortlfled microsomal enzyme system was inhibited by SKF 525-A (B-diethylaminoethyl-diphenylpropyl acetate) and by 2,4-dlchloro-6-phenylphenoxyethylamine HBr (DPEA) in a dose-dependent fashion (28). Both are known inhibitors of the classical hepatic microsomal mixed-function oxidase system. This inhibition has been suggested to Involve a nonspecific binding to liver microsomal proteins and/or phospholipids (18.19). Binding to phospholipids would support the hypothesis proposed by Swell and co-workers (10) that fatty acyl CoA derivatives were not necessarily the only immediate source for the fatty acid moieties of the conjugates that phospholipids may act as the fatty acids reservoir in the CoA-fortified enzyme system. However, it is also known that cholesterol esterification is very sensitive to the fluidity of the microsomal membrane (12). The reduced conjugation produced when... 

The nutritional status of an animal is well recognized as having an important influence on drug metabolism, disposition and toxicity. The lack of various nutrients may affect drug metabolism, though not always causing a depression of metabolic activity. Lack of protein has been particularly well studied in this respect, and shows a marked influence on drug metabolism. Thus, rats fed on low-protein diets (5%) show a marked loss of microsomal enzyme activity when compared with those animals fed a 20% protein diet (table 5,17). The decline in activity is accompanied by a decline in the level of liver microsomal protein. Both cytochrome P-450 content and cytochrome P-450 reductase activity are reduced by a 5% protein diet. 

Dalvi RR. 1987. Cytochrome P-45 0-dependent covalent binding of carbon disulfide to rat liver microsomal protein in vitro and its prevention by reduced glutathione. Arch Toxicol 61 155-157. 

Table 2 Comparison of the extent of covalent binding of radioactivity to human liver microsomal protein measured with individual tritiated analogs of compounds I-V with the amount of reactive...

Compound Covalent binding to human liver microsomal protein (pmol eq mg protein/1 h incubation) Amount of [ S]j8-mercaptoethanol adduct(s) trapped upon incubation with human liver microsomes (pmol eqmg protein/1 h incubation)... 

Rates expressed as nanomoles of product produced min" mg of rat liver microsomal protein" (Ludwig and Sprecher, 1979). 

J. Bock, M.G. Baillie, T.A. Prueksaritanont, T. Bioactivation of 2,3-diaminopyridine-containing bradyki-nin Bi receptor antagonists Irreversible binding to liver microsomal proteins and formation of glutathione conjugates. Chem. Res. Toxicol. 2005,18, 934-945. 

FIGURE 1. Rates of desaturation and chain elongation for acids in the linoleate sequence. Rates expressed as nmoles product/ min/mg microsomal protein. Each incubation for desaturation contained 10 ymoles ATP, 2 ymoles NADH, 0.3 ymole CoA, 150 ymoles potassium phosphate buffer, pH 7.4, 150 nmoles radioactive fatty acid, 5 mg liver microsomal protein from rats raised on a fat-free diet and 5 mg bovine serum albumin. Chain elongation conditions were the same except 2.0 ymoles of NADPH were used instead of NADH and 0.3 ymole of malonyl-CoA was added. All incubations were run in 1.5 ml for 3 minutes at 37°C. (Bernert Sprecher, 1975)... 

Assays were performed at 30T in lOmM Tris/HQ buffer (pH 7.4) containing 3(X)mM sucrose, bovine albumin (1 mg.ml ), 10tnMtngCl2,0.8mM EDTA and ItnM dithiothreitol. Palmitoyl-CoA and palmitoylcarnitine were used at 40mM, CoASH at lOOpM and carnitine at 200mM. All measurements were made with and without 123mM ethanol, with the difference between these measurements indicating ethylpalmitate formation. To unseal microsomal vesicles, alamethicin (lOpg.ml ) was added. Assays were initiated by the addition of 0.7mg of liver microsomal protein. All values are means SEM. 

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