Behaviors of Sodium Taurocholate and Sodium Taurodeoxycholate in Binary Mixed Micelles of Bile Salt and Nonionic Surfactant

Langmuir ◽  
1996 ◽  
Vol 12 (23) ◽  
pp. 5536-5540 ◽  
Author(s):  
K. Suzuki ◽  
T. Hasegawa ◽  
Y. Takamura ◽  
K. Takahashi ◽  
H. Asano ◽  
...  
Keyword(s):  
Bile Salt ◽  
Nonionic Surfactant ◽  
Mixed Micelles ◽  
Sodium Taurocholate ◽  
Sodium Taurodeoxycholate

scholarly journals Enzymic hydrolysis of sphingomyelin in the presence of bile salts

1980 ◽  
Vol 185 (3) ◽  
pp. 749-754 ◽  
Author(s):  
S Yedgar ◽  
S Gatt
Keyword(s):  
Bile Salt ◽  
Bile Salts ◽  
Sodium Taurocholate ◽  
Absolute Concentration ◽  
Mixed Aggregates ◽  
Sodium Taurodeoxycholate ◽  
Rate Of Hydrolysis ◽  
The Absolute ◽  
Hydrolysis Of ◽  
Low Activity

Sphingomyelin in mixed dispersion with bile salts was hydrolysed by the solubilized sphingomyelinase of rat brain lysosomes. In parallel studies, physical properties of these dispersions were determined. The kinetic curves that described the rate of hydrolysis as a function of increasing concentrations of bile salt were multiphasic. A region of very low activity was followed by an ascending portion, a peak, a descending portion, a trough and a second ascending portion. The positions of the initiation points, peaks and troughs were found to be a function of the respective ratios of the bile salt to sphingomyelin for the detergent sodium taurodeoxycholate, but of the absolute concentration of the detergent for sodium taurocholate. Turbidity studies suggested that hydrolysis of sphingomyelin begins at a bile salt concentration that solubilizes the lipid and incorporates it into a mixed micelle with the detergent. Ultracentrifugation studies suggested that the sizes of the mixed aggregates of detergent and lipid were a function of the ratio of taurodeoxycholate to sphingomyelin, but of the absolute concentration of the bile salt, for sodium taurocholate.

Behaviors of sodium glycochenodeoxycholate and sodium glycoursodeoxycholate in binary mixed micelles of bile salt and nonionic surfactant

1996 ◽  
Vol 7 (5-6) ◽  
pp. 239-247 ◽  
Author(s):  
Y. Takamura ◽  
S. Nakagawa ◽  
K. Suzuki ◽  
K. Takahashi ◽  
H. Asano ◽  
...  
Keyword(s):  
Bile Salt ◽  
Nonionic Surfactant ◽  
Mixed Micelles

Protein kinase C induces endocytosis of the sodium taurocholate cotransporting polypeptide

2010 ◽  
Vol 299 (2) ◽  
pp. G320-G328 ◽  
Author(s):  
Claudia Stross ◽  
Angelika Helmer ◽  
Katrin Weissenberger ◽  
Boris Görg ◽  
Verena Keitel ◽  
...  
Keyword(s):  
Protein Kinase C ◽  
Protein Kinase ◽  
Bile Salt ◽  
Fluorescent Protein ◽  
Membrane Surface ◽  
Sodium Taurocholate ◽  
Surface Expression ◽  
Cell Surface Expression ◽  
Salt Uptake ◽  
Kinase C

Bile salts influence signaling and metabolic pathways. In hepatocytes, the sodium taurocholate cotransporting polypeptide (Ntcp) is a major determinant of intracellular bile salt levels. Short-term downregulation of Ntcp is not well characterized to date. FLAG and enhanced green fluorescent protein (EGFP) tags were cloned to the extra- and intracellular termini of Ntcp. Endocytosis of Ntcp in transfected HepG2 cells was visualized by fluorescence of EGFP, and membrane surface expression of Ntcp was quantified by flow cytometry with fluorochrome-labeled FLAG antibodies. Activation of protein kinase C (PKC) by phorbolester or thymeleatoxin an activator of Ca2+-dependent conventional PKCs (cPKCs), induced endocytosis of Ntcp, whereas the Na+-K+-ATPase remained in the plasma membrane. The PKC inhibitor BIM I and the cPKC-selective inhibitor Gö6976 abolished PMA-induced endocytosis. Because of this internalization, cell surface expression of Ntcp was reduced by 36 ± 7%, bile salt uptake was decreased by 25%, and taurolithocholate sulfate-induced cell toxicity was prevented. In conclusion, Ca2+-dependent PKCs induce vesicular retrieval of Ntcp, thereby reducing bile salt uptake. This mechanism may protect hepatocytes from toxic intracellular bile salt concentrations.

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