Sodium cholate

Sodiiun dodecylsulfate, cetyltrimethylam-monium chloride, sodium cholate, -cyclodextrin dansylated amino acids and polycyclic aromatic hydrocarbons > 45-fold 1% in water the greatest enhancement of fluorescence is that of sodium cholate on pyrene [263]... 

It has been reported that the percolation of conductance of water/AOT/n-heptane microemulsions is assisted by sodium cholate and retarded by sodium salicylate [282]. 

Thawed microsomal preparations (500-700 mg protein) from little skates were digested with sodium cholate (1 mg/mg protein) in 10 mM potassium phosphate buffer (pH 7.7) to make a final concentration of 10 mg protein/ml, in the presence of 0.1 mM EDTA,... 

The elution profile of cytochrome P-448 (absorption at 418 nm) and epoxide hydratase activity from a sodium cholate-solubi-lized hepatic microsomal preparation (from DBA-treated male skates) applied to a DEAE-cellulose column and eluted with Buffer II is shown in Fig. 3. The void volume of the column contained significant amounts of epoxide hydratase activity. Fractions 40-70 (Fig. 3) were combined, and concentrated. The carbon monoxide difference spectrum, which had an absorption maximum at 448 nm in the induced state, is shown in Fig. 4. This form of the cytochrome (i.e.,... 

Very similar results to those described in Fig. 3-6 were obtained when sodium cholate solubilized hepatic microsomes from DBA-treated female little skates were subjected to chromatography on DEAE-cellulose as described above (data not shown). Also not shown are the results obtained with hepatic microsomes from untreated male and female little skates. With untreated animals, 80-90% of the cytochrome P-450 eluted from the DEAE-cellulose column only at higher ionic strength (i.e., with the KC1 gradient). However, in all preparations studied, an appreciable amount of cytochrome P-450 (10-20%), having its absorption maximum in the carbon monoxide-ligated and reduced state at 450 nm, was eluted from the column with buffer II, as was observed with cytochrome P-448 of hepatic microsomes from DBA-treated skates. The further purification of the various forms of cytochrome P-450 from control and DBA-pretreated little skate livers is currently in progress in our laboratory. 

The reconstituted system consisted of Cytochrome P-488 (0.2 nmol), NADPH-Cytochrome c reductase (1500 units) and sodium cholate (1.25 mg). It was preincubated for 30 min at 31°. The final reaction mixture (which was incubated at 31° for 20 min) com tained the preincubated system described above, excess NADPH and t4C-BP (100 nmol 4.1 mCi/mmol) in a final volume of 1 mL 0.5M HEPES buffer, pH 7.6. Rate of BP metabolism was 665 pmol/min/nmol Cytochrome P-488. Abbreviations used for metabolites are described in legend to Figure 2. 

Stabilization in water (surface tension 72 mN/m) can be achieved through the use of surfactants [77] such as SDBS [78] or sodium cholate [79], or long chain polymers such as polyvinyl alcohol. While this allows a non-toxic and easily removed solvent to be used, the presence of the surfactant or polymer molecules can be detrimental to the subsequent applications [80]. 

Impurity profiling by MEKC was demonstrated for the first time in 1990 for the separation of diltiazem and its impurities. MEKC employing the bile salt, sodium cholate, as the micellar phase provided satisfactory separation of diltiazem and its impurities within 15 Salicylamide and 12 of its impurities were separated within 6 min by MEKC with a... 

Detergents. Under appropriate conditions of pH, ionic strength and temperature, detergents (ionic sodium lauiyl sulphate, sodium deoxycholate, sodium cholate and cetyldiethyl-ammonium bromide, or nonionic Tweens and Tritons), can be used to lyse cells. Detergents may however cause enzyme inactivation and may need to be removed before purification. 

Sodium cholate in methanol dissolve 20 mg sodium cholate in 1 ml methanol. 

Pipette 25 pi sodium cholate in methanol in a Pyrex tube and dry with nitrogen. For each patient a duplicate sample and a duplicate blank (f=0) is measured. Add... 

Egg yolk phosphatidylcholine. Cholesterol. Cholesteryl oleate. [3H]-cholesteryl oleate. Chloroform. Ethanol. Sodium phosphate. EDTA. NaN3. Sodium cholate. NaCl. 

To prepare proteoliposomes, 7 mg egg yolk phosphatidylcholine, 1.16 pg cholesterol, 77.5 pg cholesteryl oleate and 10 pCi [3H]-cholesteryl oleate, all dissolved in chloroform are mixed. After evaporation of chloroform with nitrogen, the lipids are resolved in 400 pi ethanol. The ethanolic solution is injected into 5 ml of a vortex-ing buffer with 39mmol/l sodium phosphate, 0.01% EDTA, 2 mmol/1 NaN3, and 12 mmol/1 sodium cholate (pH 7.4) 3 mg apoA-I is added. The solution is subsequently dialyzed against a buffer with 39 mmol/1 sodium phosphate, 0.01 % EDTA, 2 mmol/1 NaN3, and 12 mmol/1 sodium cholate (pH 7.4) at 4°C. At the end the solution is filled up with analysis buffer containing 39 mmol/1 sodium phosphate,... 

Red-cell (dark adapted) Blepharisma japonicum were cultured in Pisa, in the dark, at 23 °C, in the presence of the Enterobacter aerogenes bacterium as food supply [7]. Blue-cell (light adapted) Blepharisma japonicum were produced by in vivo photoconversion of blepharismin into oxyblepharismin under a low intensity cold white lamp (below 10 W/m2). Blue cells were washed, collected by low speed centrifugation and resuspended in a 20-mM sodium cholate solution. The chromoprotein was obtained by FPLC chromatography of this preparation, on a hydroxyapatite column. The applied eluent was a phosphate buffer (pH 7.4), first 0.05 M and then 0.2 M. This ionic strength step affects the affinity of the biomolecules with the hydroxyapatite [8]. 

Different factors govern the formation of these molecular compounds. Where lipids and related substances are concerned the governing factor is the realization of the best hydrophilic-lipophilic balance producing hydration or dispersion. The case of lecithin and sodium cholate associated in the presence of water may be used to illustrate the conditions of association and formation of different types of structure and of micelles. 

Sodium cholate is insoluble in chloroform and in nonpolar solvents in general, but it is very soluble in alcohol and in water. Lecithin, on the contrary, is soluble in chloroform and only swells in water without dissolving in it. These differences in solubility are evidently related to the molecular structure and to the position of the hydrophilic groups in each of these molecules. The lecithin molecule has two important paraffinic chains and a group of hydrophilic functions (choline phosphate) localized at one end. In the presence of water, the lecithin molecules are oriented with their hydrophilic groups toward the water, and they hide their paraffinic chains inside a structure formed of two superposed layers of molecules. Conversely, in a nonpolar solvent the paraffinic chains are turned toward the solvent, while the polar groups are hidden inside the micelle. 

In addition to its carboxylic function at the end of the molecule, sodium cholate has three OH groups located on the steroid ring. This structure explains the great solubility of the cholate in water and its insolubility in the nonpolar solvents, but the three OH groups are distributed on the same side of the steroid ring, so that it is possible to talk of a lipophilic face and a hydrophilic face in the molecule. 

Two complementary experiments show that the orientation and hiding of one or the other face of the steroid ring of cholate can occur when mixtures of lecithin and bile salt are considered. One of these experiments was performed by Etienne (4), who observed the following facts incidentally while extracting lipids from the serum lipoproteins by Delsal s method. This method utilizes a mixture of methanol and methylal (1 to 4) in the cold. The proteins are precipitated, while the lipids are dissolved in the methanol-methylal solvent mixture. If this solution of the lipids is evaporated, the residue is soluble in nonpolar solvents, such as chloroform. However, if sodium cholate is added to the lipoproteins before their extraction, the residue obtained after the methylal-methanol solvent evaporates is insoluble in chloroform. More precisely, while cholesterol and the triglycerides of the lipidic residue are extracted by chloroform, all of the lecithin remains insoluble, associated to the bile salt. The explanation is probably as follows. During evaporation, methylal with its low boiling point (44°C.), evaporates first, and the solvent becomes more and more concentrated with methanol and the residual water from the lipoprotein aqueous solution. Therefore, in the lecithin plus... 

Study of solutions of bile salt in water and in particular of sodium cholate by light scattering (7) has shown that the dissolved molecules form associations of few molecules two, three, or four. 

A modified biuret reagent was formulated (sodium tartrate replaces sodium potassium tartrate, the sodium hydroxide concentration is reduced, and potassium iodide was deleted). When the modified biuret reagent was mixed with samples containing 2% detergent (SDS or sodium cholate or Triton X-I00), it resulted in less protein-to-protein variation among six proteins. 

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