The endothermic nature of the binding of anionic bile salts to a cationic adsorbent

2002 ◽  
Vol 80 (1) ◽  
pp. 89-93 ◽  
Author(s):  
Celia K Williams ◽  
William C Galley ◽  
G Ronald Brown
Keyword(s):  
Bile Salt ◽  
Thermodynamic Parameters ◽  
Driving Force ◽  
Bile Salts ◽  
Cationic Polymer ◽  
Langmuir Equation ◽  
Enthalpy Change ◽  
Polymer Sorbents ◽  
Sodium Chenodeoxycholate ◽  
Increasing Temperature

The binding of a hydrophobic bile salt, sodium chenodeoxycholate, by a polyacrylamide with N,N,N-trimethylammonium dodecyl chloride (QPDA12) pendant groups was studied to evaluate the thermodynamic parameters associated with the binding. The Langmuir equation was used in interpreting the data obtained from HPLC measurements. An increase in binding affinity was observed with increasing temperature indicating that the driving force for binding is derived from an increase in entropy (ΔS° = 253 J mol–1 K–1) despite the positive, or unfavourable, enthalpy change (ΔH° = 53 kJ mol–1). The positive thermodynamic parameters associated with the binding suggest that the disruption of hydrophobic and (or) ionic hydration associated with the bile salts and cationic polymer is the driving force for the binding.Key words: bile salts, endothermic binding, polymer sorbents, solvent randomization.

scholarly journals Equilibrium and thermodynamic studies of stearic acid adsorption on Celtek clay

2007 ◽  
Vol 72 (5) ◽  
pp. 485-494 ◽  
Author(s):  
Ahmet Sari ◽  
Mustafa Soylak
Keyword(s):  
Free Energy ◽  
Stearic Acid ◽  
Thermodynamic Parameters ◽  
Enthalpy Change ◽  
Isotherm Models ◽  
Gibbs Free Energy Change ◽  
Linear Forms ◽  
Considerable Potential ◽  
Olive Oils ◽  
Increasing Temperature

This paper presents the equilibrium and thermodynamic parameters of the adsorption of stearic acid on Celtek clay as a function of temperature. It was found that the adsorption of stearic acid on Celtek clay decreased with increasing temperature from 293 to 313 K. The equilibrium modelled data fitted well with the linear forms of both the Langmuir and the Freundlich models (R2 = 0.99 in both cases). The R L and 1/n values determined from the isotherm models proved that Celtek clay is a suitable adsorbent for stearic acid. The Dubinin-Radushkevich (D-R) isotherm was applied to describe the nature of the adsorption of stearic acid on Celtek clay and it was found that the adsorption occurred physically. Thermodynamic parameters of adsorption, such as Gibbs free energy change (?G0), enthalpy change (?H0) and enthropy change (?S0) were also calculated. These parameters showed that the adsorption of stearic acid on Celtek clay was feasible, spontaneous, and exothermic in nature. On the basis of the results, it can be concluded that Celtek clay has considerable potential for the removal of stearic acid from the main sources, such as raw and edible soybean, sunflower and olive oils.

Molecular Mechanisms in Bile Formation

Physiology ◽  
2000 ◽  
Vol 15 (2) ◽  
pp. 89-93 ◽  
Author(s):  
Peter J. Meier ◽  
Bruno Stieger
Keyword(s):  
Bile Salt ◽  
Transport Properties ◽  
Driving Force ◽  
Bile Salts ◽  
Molecular Mechanisms ◽  
Organic Anions ◽  
Molecular Physiology ◽  
Hepatic Bile ◽  
Bile Formation

Active canalicular secretion of bile salts and non-bile salt organic anions represents the major driving force of hepatic bile formation. The most important carriers involved have now been cloned on both the basolateral and canalicular sides of hepatocytes. Elucidation of their structure, transport properties, and regulation is an important step forward in the ultimate understanding of the molecular physiology of bile formation.

The influence of competing factors on the endothermic nature of bile salt binding by cationic adsorbent

2003 ◽  
Vol 81 (2) ◽  
pp. 133-140
Author(s):  
Celia K Williams ◽  
William C Galley ◽  
G Ronald Brown
Keyword(s):  
Bile Salt ◽  
Dominant Role ◽  
Binding Constants ◽  
Debye Screening ◽  
Polymer Sorbents ◽  
Competing Anions ◽  
Sodium Chenodeoxycholate ◽  
Added Salt ◽  
Hplc Data

The binding of sodium chenodeoxycholate, a hydrophobic bile salt, by a polyacrylamide resin with N,N,N-trimethylammonium dodecyl chloride (QPDA12) pendant groups was studied in the presence of elevated concentrations of competing anions. The equilibrium bile salt concentration was determined from HPLC data for a range of initial bile salt concentrations. Binding constants extracted from the fit of the isotherms to the Langmuir equation were obtained for data for temperatures from 24 to 60°C. A reduction in chenodeoxycholate binding affinity was observed in comparison with that reported previously at lower overall anion concentrations. A van't Hoff analysis of the data revealed that a decrease in the favourable entropy of binding was responsible for this reduced affinity. Decomposition of the binding constants into specific contributions for the competing buffer anions and the chenodeoxycholate anion returned positive values of ΔH° and ΔS° for the binding of both the competing ions and bile salt. These findings reveal that the weakening of the bile salt binding that occurs with added salt is not due to Debye screening of an attraction between ions of opposite charge. A binding mechanism consistent with the thermodynamics observed was proposed in which the dominant role of hydration changes that occur on binding provides the principal driving force for the process.Key words: bile salts, endothermic binding, polymer sorbents, solvent randomization.

scholarly journals STUDI VIABILITAS ISOLAT BAKTERI ASAM LAKTAT YANG DIISOLASI DARI ASINAN REBUNG BAMBU TABAH TERHADAP pH RENDAH DAN GARAM EMPEDU

2019 ◽  
Vol 7 (1) ◽  
pp. 1 ◽  
Author(s):  
Nurul Octavia Wasis ◽  
Nyoman Semadi Antara ◽  
Ida Bagus Wayan Gunam
Keyword(s):  
Lactic Acid ◽  
Lactic Acid Bacteria ◽  
Bile Salt ◽  
Bile Salts ◽  
Salt Resistance ◽  
Low Ph ◽  
Fermented Food ◽  
Bamboo Shoot ◽  
Probiotic Lactic Acid Bacteria ◽  
Mrs Broth

Tabah bamboo shoot pickle is one of the fermented food which is the source of lactic acid bacteria.  Lactic acid bacteria (LAB) is beneficial to health because it has the ability as a probiotic. Lactic acid bacteria that have probiotic criteria should have resistance to low pH and bile salts. This study aims to determine isolates of lactic acid bacteria isolated from tabah bamboo shoot pickle resistant to low pH and bile salts (NaDC). Lactic acid bacteria were tested to low pH by using MRS broth that have different pH (pH 2, pH 3, pH 4 and pH 6.2 as a control) incubated at 37ºC for 3 hours. isolates were survive in low pH then continued in bile salt resistance test with 0.3% bile salt concentration for 15 minutes, 30 minutes, 45 minutes, 60 minutes and 24 hours. The results showed that three isolates out of 88 isolates had ability to grow in low pH and in medium supplemented by NaDC 0,3%. The isolates are AR 3057, AR 3101 and AR 6152 which can be used as candidat of  probiotic. Keywords : Tabah bamboo shoot pickle, lactic acid bacteria, probiotic, low pH, bile salt

scholarly journals Regulation of mdr2 P-glycoprotein expression by bile salts

1997 ◽  
Vol 321 (2) ◽  
pp. 389-395 ◽  
Author(s):  
Charles M. G. FRIJTERS ◽  
Roelof OTTENHOFF ◽  
Michel J. A. van WIJLAND ◽  
Carin M. J. van NIEUWKERK ◽  
Albert K. GROEN ◽  
...  
Keyword(s):  
Bile Salt ◽  
Bile Salts ◽  
Control Diet ◽  
Mrna Level ◽  
Northern Blotting ◽  
Mrna Levels ◽  
Male Mice ◽  
Complete Replacement ◽  
P Glycoprotein ◽  
Mrna Content

The phosphatidyl translocating activity of the mdr2 P-glycoprotein (Pgp) in the canalicular membrane of the mouse hepatocyte is a rate-controlling step in the biliary secretion of phospholipid. Since bile salts also regulate the secretion of biliary lipids, we investigated the influence of the type of bile salt in the circulation on mdr2 Pgp expression and activity. Male mice were fed a purified diet to which either 0.1% (w/w) cholate or 0.5% (w/w) ursodeoxycholate was added. This led to a near-complete replacement of the endogenous bile salt pool (mainly tauromuricholate) by taurocholate or tauroursodeoxycholate respectively. The phospholipid secretion capacity was then determined by infusion of increasing amounts of tauroursodeoxycholate. Cholate feeding resulted in a 55% increase in maximal phospholipid secretion compared with that in mice on the control diet. Northern blotting revealed that cholate feeding increased mdr2 Pgp mRNA levels by 42%. Feeding with ursodeoxycholate did not influence the maximum rate of phospholipid output or the mdr2 mRNA content. Female mice had a higher basal mdr2 Pgp mRNA level than male mice, and this was also correlated with a higher phospholipid secretion capacity. This could be explained by the 4-fold higher basal cholate content in the bile of female compared with male mice. Our results suggest that the type of bile salts in the circulation influences the expression of the mdr2 gene.

scholarly journals Characteristics of bile salt uptake into skate hepatocytes

1994 ◽  
Vol 299 (3) ◽  
pp. 665-670 ◽  
Author(s):  
G Fricker ◽  
V Dubost ◽  
K Finsterwald ◽  
J L Boyer
Keyword(s):  
Substrate Specificity ◽  
Bile Salt ◽  
Transport System ◽  
Bile Salts ◽  
Organic Anion ◽  
Anion Transport ◽  
Organic Anion Transport ◽  
Salt Uptake ◽  
Anion Transport System ◽  
Alpha 7

The substrate specificity for the transporter that mediates the hepatic uptake of organic anions in freshly isolated hepatocytes of the elasmobranch little skate (Raja erinacea) was determined for bile salts and bile alcohols. The Na(+)-independent transport system exhibits a substrate specificity, which is different from the specificity of Na(+)-dependent bile salt transport in mammals. Unconjugated and conjugated di- and tri-hydroxylated bile salts inhibit uptake of cholyltaurine and cholate competitively. Inhibition is significantly greater with unconjugated as opposed to glycine- or taurine-conjugated bile salts. However, the number of hydroxyl groups in the steroid moiety of the bile salts has only minor influences on the inhibition by the unconjugated bile salts. Since the transport system seems to represent an archaic organic-anion transport system, other anions, such as dicarboxylates, amino acids and sulphate, were also tested, but had no inhibitory effect on bile salt uptake. To clarify whether bile alcohols, the physiological solutes in skate bile, share this transport system, cholyltaurine transport was studied after addition of 5 beta-cholestane-3 beta,5 alpha,6 beta-triol, 5 alpha-cholestan-3 beta-ol and 5 beta-cholestane-3 alpha, 7 alpha, 12 alpha-triol. These bile alcohols inhibit cholyltaurine uptake non-competitively. In contrast, uptake of 5 beta-cholestane-3 alpha,7 alpha,12 alpha-triol, which is Na(+)-independent, is not inhibited by cholyltaurine. The findings further characterize a Na(+)-independent organic-anion transport system in skate liver cells, which is not shared by bile alcohols and has preference for unconjugated lipophilic bile salts.

scholarly journals Studies on the interactions between bile salts and food emulsifiers under in vitro duodenal digestion conditions to evaluate their bile salt binding potential

2019 ◽  
Vol 174 ◽  
pp. 493-500 ◽  
Author(s):  
Julieta N. Naso ◽  
Fernando A. Bellesi ◽  
Víctor M. Pizones Ruiz-Henestrosa ◽  
Ana M.R. Pilosof
Keyword(s):  
Bile Salt ◽  
Bile Salts ◽  
Binding Potential ◽  
Food Emulsifiers

Hepatic bile flow

1984 ◽  
Vol 64 (4) ◽  
pp. 1055-1102 ◽  
Author(s):  
R. C. Strange
Keyword(s):  
Bile Salt ◽  
Bile Salts ◽  
Basolateral Membrane ◽  
Membrane Vesicles ◽  
Critical Micellar Concentration ◽  
Canalicular Membrane ◽  
Receptor Proteins ◽  
Subcellular Organelles ◽  
Golgi Bodies ◽  
Initial Event

The hepatocyte is a polar cell that can remove a variety of molecules from blood and excrete them into bile. This review is primarily concerned with the mechanism of transport of the principal anions--the bile salts--across the sinusoidal membrane, their passage through the cell, and excretion across the canalicular membrane. Clearly much of this process is poorly understood, but the study of the membrane stages should be facilitated by the ability to prepare purified sinusoidal and canalicular membrane vesicles. For example, the relative importance of albumin-binding sites as well as the putative bile salt receptor proteins can be better assessed. It seems likely that although the interaction of bile salts with receptor proteins is important, it is an initial event that puts the bile salt in the correct place for uptake to occur. The driving force for uptake is the Na+ gradient created across the basolateral membrane by the activity of the Na+-K+-ATPase. Within the cell, various modes of transport have been suggested. Several authors emphasize the importance of protein binding of bile salts, either because of their presumed ability to maintain the concentration of these anions in the hepatocyte below their critical micellar concentration or because of their putative role in transport. It is important to understand these aspects of the role of cytosolic proteins for several reasons. Knowledge of the true concentration of free bile salt within the cell should allow estimation of whether the electrochemical gradient is sufficient for bile salts to accumulate in bile without the need for active transport of molecules from the cell into the canaliculus. The compartmental model described by Strange et al. (153) offers one theoretical way of determining the concentration of free bile salt, although the problems inherent in studying amphipath binding to the membranes of subcellular organelles (31) require that the model be reevaluated by the hygroscopic-desorption method. The second role suggested for the cytosolic bile salt-binding proteins is as transport proteins. As discussed in section VI, I think it is unlikely that the proteins identified so far act in this way, and it is more likely that movement occurs by diffusion in free solution. It is also important to determine the possible involvement of subcellular organelles such as Golgi bodies. Little is known of their role in the transport of bile salts or indeed where bile salt micelles are formed.(ABSTRACT TRUNCATED AT 400 WORDS)

Effect of intestinal resection on bile salt absorption in dogs

1965 ◽  
Vol 208 (2) ◽  
pp. 363-369 ◽  
Author(s):  
M. R. Playoust ◽  
Leon Lack ◽  
I. M. Weiner
Keyword(s):  
Bile Salt ◽  
Bile Salts ◽  
Enterohepatic Circulation ◽  
Sodium Taurocholate ◽  
Intestinal Resection ◽  
High Fat ◽  
Salt Absorption ◽  
Complete Failure ◽  
Fat Meal

The efficiency of intestinal absorption of bile salts was evaluated by studying the rate of disappearance of radioactivity from the bile of dogs after the intravenous administration of sodium taurocholate-24-C14. Bile was sampled through an indwelling tube in the gall bladder. One day after a high-fat meal normal dogs retained 48% of the radioactivity; dogs with resection of the jejunum retained 48%, whereas those with resection of the ileum retained only 3% in the bile. This is consistent with previous observations that the ileum is the site of bile salt absorption in vitro and in anesthetized animals. Animals with resection of the ileum exhibited significant steatorrhea; however, three-fourths of the ingested fat was absorbed in spite of almost complete failure to absorb bile salts. This indicates that fat and bile salts are not normally absorbed together. Elimination of enterohepatic circulation of bile salts by resection of the ileum contributes to the observed steatorrhea.

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