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.

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.

Effect of glycodihydrofuisidate on sulfobromophthalein transport maximum in the hamster

1976 ◽  
Vol 231 (6) ◽  
pp. 1875-1878 ◽  
Author(s):  
Y Delage ◽  
M Dumont ◽  
S Erlinger
Keyword(s):  
Bile Salt ◽  
Transport System ◽  
Bile Salts ◽  
Sodium Taurocholate ◽  
Specific Effect ◽  
Biliary Secretion ◽  
Biliary Lipid ◽  
Lipid Secretion ◽  
Dye Transport ◽  
Cholesterol Secretion

The effect on sulfobromophathalein transport maximum (Tm) and biliary lipid secretion of sodium glyco-24,25-dihydrofusicate, a micelle-forming compound secreted into bile, has been studied in the hamster and compared to that of a physiological bile salt, sodium taurocholate. Biliary phospholipid and cholesterol secretion increased both during glycodihydrofusidate and taurocholate administration, an observation which suggest that both compounds increased th biliary secretion of micelle-forming compounds. In contrast, only taurocholate increased sulfobromophthalein Tm into bile, while glycodihydrofusidate administration decreased it. This observation suggests that the increase in sulfobromophthalein Tm observed during taurocholate administration is not the result of micellar sequestration. It could rather be the consequence of a specific effect of bile salts on the dye transport system.

How does bile salt penetration affect the self-assembled architecture of pluronic P123 micelles? – light scattering and spectroscopic investigations

2015 ◽  
Vol 17 (30) ◽  
pp. 19977-19990 ◽  
Author(s):  
Arpita Roy ◽  
Niloy Kundu ◽  
Debasis Banik ◽  
Jagannath Kuchlyan ◽  
Nilmoni Sarkar
Keyword(s):  
Light Scattering ◽  
Bile Salt ◽  
Bile Salts ◽  
Triblock Copolymer ◽  
Sodium Taurocholate ◽  
Sodium Deoxycholate ◽  
The Self ◽  
Spectroscopic Investigations ◽  
Pluronic P123 ◽  
Supramolecular Aggregate

The triblock copolymer of the type (PEO)20–(PPO)70–(PEO)20 (P123) forms a mixed supramolecular aggregate with different bile salts, sodium deoxycholate (NaDC) and sodium taurocholate (NaTC), having different hydrophobicity.

scholarly journals Substrate specificity and mode of action of a cellulase from Aspergillus niger

1978 ◽  
Vol 169 (2) ◽  
pp. 389-395 ◽  
Author(s):  
P L Hurst ◽  
P A Sullivan ◽  
M G Shepherd
Keyword(s):  
Aspergillus Niger ◽  
Substrate Specificity ◽  
Mode Of Action ◽  
Cellulose Derivatives ◽  
Polygalacturonic Acid ◽  
Glycol Chitosan ◽  
Glucose Polymer ◽  
Rate Of Hydrolysis ◽  
Hydrolysis Of ◽  
Low Activity

The mode of action and substrate specificity of a cellulase purified from Aspergillus niger were examined. The enzyme showed little capacity to hydrolyse highly ordered cellulose, but readily attacked soluble cellulose derivatives and amorphous alkali-swollen cellulose. Activity towards barley glucan and lichenin was greater than with CM-cellulose. Low activity was detected with CM-pachyman (a substituted beta-1,3-glucose polymer) and xylan. Activity towards yeast glucan, mannan, ethlene glycol chitin, glycol chitosan, laminarin, polygalacturonic acid and pectin could not be demonstrated. Cellobiose and p-nitrophenyl beta-D-glucoside were not hydrolysed, whereas the rate of hydrolysis of the higher members of the reduced cellulodextrins increased with chain length. The central bonds of cellotetraosylsorbitol and cellopentaosylsorbitol were the preferred points of clevage. Kinetic data indicated that the specificity region of the cellulase is five glucose units in length. The evidence indicates that the cellulase is an endoglucanase.

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 Spectrophotometric determination of the critical micellar concentration of bile salts using bilirubin monoglucuronide as a micellar probe. Utility of derivative spectroscopy

1988 ◽  
Vol 252 (1) ◽  
pp. 275-281 ◽  
Author(s):  
W Spivak ◽  
C Morrison ◽  
D Devinuto ◽  
W Yuey
Keyword(s):  
Bile Salt ◽  
Bile Salts ◽  
Sodium Taurocholate ◽  
Critical Micellar Concentration ◽  
Relative Energy ◽  
Bile Pigment ◽  
Sharp Change ◽  
Derivative Spectroscopy ◽  
Invasive Method ◽  
Sudden Decrease

We have developed a simple biologically non-invasive method for determining the critical micellar concentration (CMC) of bile salts using pure naturally occurring bilirubin IX alpha monoglucuronide (BMG), an important bile pigment present in virtually all mammalian biles. This methodology employs visible absorbance spectroscopy of BMG in bile salts over a range of bile salt concentrations that include the reported CMC. Using 100 microM-BMG in 0.4 M-imidazole buffer at pH 7.8, we calculated that the CMC for sodium taurochenodeoxycholate is between 2.5 and 3.0 mM based on: (1) an abrupt change in lambda max. in this concentration range, (2) a precipitous decrease in the amplitude of the absorbance shoulder at 450 nm, (3) a sudden decrease in the second derivative absorbance of BMG at 400 nm and an increase in absorbance at 470 nm, (4) a sharp change in the 4th derivative absorbance at 375 and 395 nm. In contrast, sodium taurocholate, a bile salt that reportedly does not have a CMC but continuously self-associates over a wide concentration range, exhibited none of these changes. The use of derivative spectroscopy enhances the ability to detect the CMC changes and also indicates the number of BMG species in solution and their relative energy states.

Studies in Bile Salt Solutions .XIII. Hydrophobic Substrate Effects on the Esterase Activity of Bile-Salt-Stimulated Human-Milk Lipase. Hydrolysis of 4-Nitrophenyl Alkanoates and Alkyl 4-Nitrobenzoates

1986 ◽  
Vol 39 (2) ◽  
pp. 249 ◽  
Author(s):  
CJ Oconnor ◽  
ASH Mitha ◽  
P Walde
Keyword(s):  
Human Milk ◽  
Bile Salt ◽  
Binding Site ◽  
Sodium Taurocholate ◽  
Sodium Cholate ◽  
Lipase Hydrolysis ◽  
Nitrobenzoic Acid ◽  
Hydrocarbon Chains ◽  
Hydrophobic Nature ◽  
Hydrolysis Of

The pseudo-first-order rate constants of hydrolysis of a series of 4-nitrophenyl alkanoates and a series of n-alkyl esters of 4-nitrobenzoic acid and of 4-nitrophenyl hexahydrobenzoate and cyclohexyl 4-nitrobenzoate, catalysed by bile-salt-stimulated human milk lipase in the absence and presence (2 mmol dm-3) of sodium cholate/cholic acid and sodium taurocholate , have been measured at pH 7.3, 310.5 K. It has been shown that the enzyme possesses a specific esterase acyl binding site which almost completely excludes the binding therein of a cyclohexyl group. There is also present a specific alkyl binding site which can fully accommodate a cyclohexyl ring. Both binding sites are hydrophobic in nature, but although the hydrophobic nature of the alkyl binding site is affected by bile-salt stimulation, that of the acyl site is not. Hydrophobicity parameters have been calculated for hydrocarbon chains lying in the acyl and alkyl binding positions of bile-salt-stimulated human milk lipase.

Ileal transposition into the upper jejunum affects lipid and bile salt absorption in rats

1996 ◽  
Vol 271 (4) ◽  
pp. G681-G691 ◽  
Author(s):  
T. Tsuchiya ◽  
T. J. Kalogeris ◽  
P. Tso
Keyword(s):  
Bile Salt ◽  
Bile Salts ◽  
Sodium Taurocholate ◽  
Cholesterol Absorption ◽  
Lymphatic Transport ◽  
Proximal Jejunum ◽  
Ileal Transposition ◽  
Sham Surgery ◽  
Salt Absorption ◽  
Lymph Duct

To determine whether ileal transposition affects absorption and transport of lipids and bile salts, we studied the absorption and lymphatic transport of triglyceride, cholesterol, and sodium taurocholate in rats with the distal quarter of their small bowel transposed to the proximal jejunum and in control rats whose intestines were transected and reanastomosed without transposition. Three weeks after transposition or sham surgery, rats were equipped with duodenal or jejunal and intestinal lymph duct cannulas and then given continuous duodenal or jejunal infusions of lipid emulsion containing triolein (40 mumol/h + [3H]triolein) and cholesterol (7.8 mumol/h + [14C]cholesterol) for 8 h. Lymph lipid output was measured; after 8 h of lipid infusion, luminal and mucosal radioactive lipid distribution was also quantified. Transposition had no effect on triglyceride absorption and transport, but cholesterol absorption and transport were both significantly attenuated in the transposed rats. In a separate study we examined whether ileal transposition would alter the kinetics of bile salt absorption. Six weeks after either transposition or sham surgery, rats were given a duodenal bolus injection of 14C-labeled sodium taurocholate mixed in rat bile, and the output of radiolabeled bile salt through a bile fistula was measured. Appearance of radiolabeled taurocholate was gradual in the control rats, peaking at approximately 90 min after administration. Appearance of labeled bile salt was rapid in the transposed rats, peaking within 60 min after administration. In conclusion, ileal transposition has no effect on triglyceride absorption but attenuates cholesterol absorption and transport, possibly by promoting premature absorption of bile salts.

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