Hydrolysis of membrane-bound liver alkaline phosphatase by GPI-PLD requires bile salts

1996 ◽  
Vol 271 (4) ◽  
pp. G655-G663 ◽  
Author(s):  
J. T. Deng ◽  
M. F. Hoylaerts ◽  
M. E. De Broe ◽  
V. O. van Hoof
Keyword(s):  
Alkaline Phosphatase ◽  
Bile Salt ◽  
Bile Salts ◽  
Small Range ◽  
Liver Sinusoid ◽  
Gpi Anchor ◽  
Low Concentrations ◽  
Membrane Bound ◽  
Triton X

Circulating liver plasma membrane fragments (LPMF) were purified from human serum by means of a monoclonal antileucine aminopeptidase antibody, AD-1. This was done by immunoaffinity chromatography or by incubating the sera with AD-1-coated nitrocellulose disks. Alkaline phosphatase (ALP, EC 3.1.3.1) is bound to these LPMF through a glycosylphosphatidylinositol (GPI) anchor and is referred to as membrane-bound liver ALP (Mem-LiALP). Low concentrations of Triton X-100 or high bile salt concentrations released GPI anchor-bearing LiALP (Anch-LiALP) from purified LPMF; once released, Anch-LiALP was slowly and progressively converted to hydrophilic dimeric LiALP [soluble LiALP (Sol-LiALP)], free from its GPI anchor. Low levels of GPI-specific phospholipase D (GPI-PLD) activity were measured in the pure LPMF. Apparently, this membrane-associated GPI-PLD was released by the action of detergents and contributed to the spontaneous conversion of Anch-LiALP to Sol-LiALP. In the absence of detergents, GPI-PLD had little effect on Mem-LiALP, both in purified form as well as in serum. In vitro, isolated Anch-LiALP was converted to Sol-LiALP by both GPI-specific phospholipase C and GPI-PLD. Sol-LiALP in serum, however, appeared to be the product of GPI-PLD activity only. Five- to tenfold higher concentrations of Triton X-100 were needed to release Anch-LiALP from LPMF in serum, compared with those required in a solution of purified LPMF. In serum, as well as in purified conditions, only a small range of detergent of bile salt concentrations permitted the conversion of Mem-LiALP to Sol-LiALP. A model is proposed for the release in the circulation of Mem-LiALP, Anch-LiALP, and Sol-LiALP, involving both LPMF-associated GPI-PLD and liver sinusoid bile salts.

scholarly journals Effects of bile salts on the plasma membranes of isolated rat hepatocytes

1980 ◽  
Vol 188 (2) ◽  
pp. 321-327 ◽  
Author(s):  
D Billington ◽  
C E Evans ◽  
P P Godfrey ◽  
R Coleman
Keyword(s):  
Alkaline Phosphatase ◽  
Bile Salt ◽  
Bile Salts ◽  
Plasma Membranes ◽  
Rat Hepatocytes ◽  
Isolated Hepatocytes ◽  
Soluble Form ◽  
Isolated Rat Hepatocytes ◽  
Low Concentrations

The conjugated trihydroxy bile salts glycocholate and taurocholate removed approx. 20–30% of the plasma-membrane enzymes 5′-nucleotidase, alkaline phosphatase and alkaline phosphodiesterase I from isolated hepatocytes before the onset of lysis, as judged by release of the cytosolic enzyme lactate dehydrogenase. The conjugated dihydroxy bile salt glycodeoxycholate similarly removed 10–20% of the 5′-nucleotidase and alkaline phosphatase activities, but not alkaline phosphodiesterase activity; this bile salt caused lysis of hepatocytes at approx. 10-fold lower concentrations (1.5–2.0mM) than either glycocholate or taurocholate (12–16mM). At low concentrations (7 mM), glycocholate released these enzymes in a predominantly particulate form, whereas at higher concentrations (15 mM) glycocholate further released these components in a predominantly ‘soluble’ form. Inclusion of 1% (w/v) bovine serum albumin in the incubations had a small protective effect on the release of enzymes from hepatocytes by glycodeoxycholate, but not by glycocholate. These observations are discussed in relation to the possible role of bile salts in the origin of some biliary proteins.

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

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.

INACTIVATION OF RENIN IN A MIXED MITOCHONDRIAL-LYSOSOMAL FRACTION OF POST-PARTUM UTERUS

1979 ◽  
Vol 92 (4) ◽  
pp. 731-745
Author(s):  
Jørgen Jørgensen
Keyword(s):  
Alkaline Phosphatase ◽  
Post Partum ◽  
Similar Rate ◽  
Freezing And Thawing ◽  
Lysosomal Fraction ◽  
Triton X

ABSTRACT The marked renin inactivation seen during in vitro incubation of post-partum uterine slices which mimics the in vivo condition, is not accompanied by a similar general proteolysis. The inactivating mechanism is so far non-specific with respect to organ or species as added hog renal renin is inactivated at a similar rate as endogenous renin. Endogenous alkaline phosphatase is not significantly inactivated and added alkaline phosphatase is completely stable. A marked inactivation of endogenous renin also takes place during incubation of a mixed mitochondrial-lysosomal suspension prepared from post-partum uterus. The process is more pronounced at pH 7.4 than at 6.8. Freezing and thawing and addition of Triton X-100 prior to incubation inhibits the inactivation. ATP and α-ketoglutarate slightly stimulates the process while CoA and chloroquine have no effect. Both iodoacetate and phenylmethylsulphonylfluoride inhibit the inactivation, suggesting that more than one enzyme is involved in the inactivation.

scholarly journals Purification, characterization and in vitro bile salt-binding capacity of polysaccharides from Armillaria mellea mushroom

2019 ◽  
Vol 37 (No. 1) ◽  
pp. 51-56 ◽  
Author(s):  
Chonghui Yue ◽  
Xiaodan Zang ◽  
Chao Chen ◽  
Liangwei Dong ◽  
Yanqiu Liu ◽  
...  
Keyword(s):  
Bile Salt ◽  
Bile Salts ◽  
Binding Capacity ◽  
Monosaccharide Composition ◽  
Composition Analysis ◽  
Enzymatic Extraction ◽  
Armillaria Mellea ◽  
Ethanol Precipitation ◽  
Ultrasound Assisted

The crude polysaccharides from Armillaria mellea were obtained with an ultrasound assisted enzymatic extraction and ethanol precipitation. Two polysaccharide fractions were obtained by ethanol precipitation, which were named AMP-1 and AMP-2. The results of the monosaccharide composition analysis indicated that AMP-1 was composed of mannose, rhamnose, glucose, galactose, arabinose and fucose and that AMP-2 was composed of mannose, rhamnose, glucose, galactose and fucose. Glucose and galactose were the main monosaccharide fractions. The protein and nucleic acid contents in AMP-1 and AMP-2 were detected by using ultraviolet and infrared spectroscopy. The bile salt-binding capacities of the polysaccharide samples were studied in vitro. In comparison with lentinan (LP), AMP-1 and AMP-2 showed increased bile salt-binding capacity. AMP-1 showed the highest binding capacity against all the bile salts. The findings presented in this study highlight the potential of the A. mellea polysaccharides as a natural hypolipidaemic agent.

scholarly journals Histochemical identification of the vascular endothelial isoenzyme of alkaline phosphatase.

1989 ◽  
Vol 37 (12) ◽  
pp. 1893-1898 ◽  
Author(s):  
H F Zoellner ◽  
N Hunter
Keyword(s):  
Alkaline Phosphatase ◽  
Physiological Role ◽  
Freeze Substitution ◽  
Differential Sensitivity ◽  
Rat Tissues ◽  
Microvascular Endothelium ◽  
Membrane Bound ◽  
Specific Inhibitors

Alkaline phosphatase (AP) is a widely studied membrane bound ecto-enzyme with an extensive distribution in nature. Three major human isoenzymes have been defined and can be distinguished on the basis of their differential sensitivity to specific inhibitors. Despite the voluminous literature describing AP, the physiological role of this enzyme is unclear. Microvascular endothelium is strongly AP positive and may provide a convenient model for study of the role of AP in vitro. This report describes the use of freeze-substitution and high-resolution plastic embedding techniques to identify the isoenzyme of endothelial AP by quantitative analysis of the relative inhibition by specific inhibitors of AP, using human gingival tissues and a number of rat tissues. Endothelial AP is found to be the liver/bone/kidney isoenzyme, indicating kidney as a credible source of enzyme for further experimental work investigating the role of AP.

PHOSPHATASE OF RABBIT POLYMORPHONUCLEAR LEUCOCYTES

1949 ◽  
Vol 27e (5) ◽  
pp. 290-307 ◽  
Author(s):  
D. M. Cram ◽  
R. J. Rossiter
Keyword(s):  
Alkaline Phosphatase ◽  
Enzyme Activity ◽  
Acid Phosphatase ◽  
Bile Salts ◽  
Polymorphonuclear Leucocytes ◽  
Alkyl Sulphate ◽  
Low Concentrations ◽  
Activity Curve ◽  
Surface Active ◽  
Active Substances

Rabbit polymorphonuclear leucocytes contain an active phosphatase that readily hydrolyzes disodium phenyl phosphate. The pH activity curve of the enzyme was found to have two maxima, one in the region of pH 10 and the other in the region of pH 5. The alkaline phosphatase was much more active than the acid phosphatase. The concentration of alkaline phosphatase in rabbit white cells was approximately one thousand times that of the enzyme in the serum. Under the conditions of study, the alkaline phosphatase activity was proportional to the concentration of the enzyme. The effect of substrate concentration on the enzyme activity was studied and the Michaelis constant (Ks) determined. An excess of substrate inhibited the enzyme. The course of the reaction was linear with time for the first 60 min.; after 90 min. the activity fell off faster than would be expected if the reaction were of the first order.Magnesium and glycine, in low concentrations, caused an increase in the enzyme activity, whereas zinc, cyanide, borate, phosphate, bile salts, and glycine, in higher concentrations, were inhibitory. Fluoride had no demonstrable effect. Surface-active substances, such as saponin, bile salts, or alkyl sulphate, liberated the enzyme from the cells. Similar results were obtained when α-glycerophosphate or β-glycerophosphate was used as the substrate.The alkaline phosphatase can be considered to belong to Class AI of Folley and Kay (22) and the acid phosphatase to Class AII. The alkaline phosphatase can also be considered to be a Phosphatase II of Cloetens (9).

scholarly journals In Vitro Hypocholesterolemic Effect of Coffee Compounds

Nutrients ◽  
2020 ◽  
Vol 12 (2) ◽  
pp. 437
Author(s):  
Filipe Manuel Coreta-Gomes ◽  
Guido R. Lopes ◽  
Cláudia P. Passos ◽  
Inês M. Vaz ◽  
Fernanda Machado ◽  
...  
Keyword(s):  
Bile Salt ◽  
Bile Salts ◽  
Soluble Fiber ◽  
Hexane Extraction ◽  
Selective Precipitation ◽  
Food Ingredients ◽  
Espresso Coffee ◽  
Coffee Lipids ◽  
Cholesterol Solubility

(1) Background: Cholesterol bioaccessibility is an indicator of cholesterol that is available for absorption and therefore can be a measure of hypocholesterolemic potential. In this work, the effect of commercial espresso coffee and coffee extracts on cholesterol solubility are studied in an in vitro model composed by glycodeoxycholic bile salt, as a measure of its bioaccessibility. (2) Methods: Polysaccharide extracts from coffees obtained with different extraction conditions were purified by selective precipitation with ethanol, and their sugars content were characterized by GC-FID. Hexane extraction allowed us to obtain the coffee lipids. Espresso coffee samples and extracts were tested regarding their concentration dependence on the solubility of labeled 13C-4 cholesterol by bile salt micelles, using quantitative 13C NMR. (3) Results and Discussion: Espresso coffee and coffee extracts were rich in polysaccharides, mainly arabinogalactans and galactomannans. These polysaccharides decrease cholesterol solubility and, simultaneously, the bile salts’ concentration. Coffee lipid extracts were also found to decrease cholesterol solubility, although not affecting bile salt concentration. (4) Conclusions: Coffee soluble fiber, composed by the arabinogalactans and galactomannans, showed to sequester bile salts from the solution, leading to a decrease in cholesterol bioaccessibility. Coffee lipids also decrease cholesterol bioaccessibility, although the mechanism of action identified is the co-solubilization in the bile salt micelles. The effect of both polysaccharides and lipids showed to be additive, representing the overall effect observed in a typical espresso coffee. The effect of polysaccharides and lipids on cholesterol bioaccessibility should be accounted on the formulation of hypocholesterolemic food ingredients.

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