Gene/Protein Disease Symptom Drug Enzyme Compound
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Query: EC:3.1.3.1 (alkaline phosphatase)
 47,916 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

Brush borders were prepared from pig intestinal mucosa and the membrane proteins solubilized with either Triton X-100 or papain. Proteins, thus released, were used as antigens to raise antisera in rabbits. The immunoglobulin G fractions were isolated and shown by the double layer immunofluorescence staining technique to react only with the brush border region of the enterocyte. The antibodies obtained were used in immunoelectrophoretic studies on the brush border proteins. Eight hydrolytic activities were identified by the use of histo-chemical staining methods. These were the microsomal aminopeptidase (EC 3.4.11.2), aspartate aminopeptidase (EC 3.4.11.7), dipeptidyl peptidase IV (EC 3.4.14.X), lactase (EC 3.2.1.23), glucoamylase (EC 3.2.1.3), sucrase (EC 3.2.1.48), isomaltase (EC 3.2.1.10) and alkaline phosphatase (EC 3.1.3.1). In addition, at least four faint immunoprecipitates were formed but none of these were identified.
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PMID:Immunoelectrophoretic studies on pig intestinal brush border proteins. 2 Sep 74

Amphipathic enzymes, invertase (EC 3.2.1.26), 8-amylase (EC 3.2.1.3), and alkaline phosphatase (EC 3.1.3.1), were purified from the rat small intestinal mucosa as trypsin and Triton forms, the catalytic and regulatory characteristics of which were compared in rats and in drosophila. Differences in the catalytic propertiis of the two enzyme forms were demonstrated, which suggested that the hydrophobic part of the enzyme was involved in maintaining optimal conformation of the catalytic part. Many modifiers have beenfound to influence the Triton rather than the trypsin form of the enzyme. It is therefore suggested that the hydrophobic sub-units of the enzymes might be involved in transmitting information from the cytoplasm into the external surface of the membrane, the cell in this way regulating the activity of surface enzymes. If this is indeed the case, it is suggested that the hydrophobic part performs functions not only of external but also of internal regulation.
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PMID:Catalytic and regulatory properties of the Triton and trypsin forms of the brush border hydrolases. 4 Aug 47

At various postnatal stages, intestinal epithelial cells were isolated sequentially from villus tip to crypt base by successive EDTA treatments. According to the localization of marker enzymic activities, isolated cells were pooled into three cell compartments: villus (V), lower villus and upper crypt (VC) and crypt (C). Purified brush-border-membrane proteins were separated by 7.5%-polyacrylamide-gel electrophoresis in the presence of sodium dodecyl sulphate. Enzymic activities could be assigned to some protein bands: maltase/glucoamylase (protein band 3), sucrase-isomaltase (protein bands 3 and 6), lactase (protein band 5) and alkaline phosphatase (region of protein bands 8 and 9). The findings suggest the following. (1) Sucrase-isomaltase activities appeared in compartment C at 17 days with a simultaneous increase of the pre-existing protein band 3 and appearance of a well-defined protein band in position 6; the enzymic complex remained still present in the crypt cells until adulthood. From the day 21 onwards, sucrase-isomaltase was detected in compartments VC and V. (2) Lactase was only present in the three cell compartments until day 21; at this developmental stage its activity completely disappeared from compartment C, in spite of the persistence of a weak protein band. (3) Alkaline phosphatase activity could be detected as a single peak corresponding to protein band 9 in all three cell compartments until day 21; thereafter it was replaced by two peaks of activity showing a less precise correlation with the well-defined protein bands 8 and 9. In the crypt cells of the adult rat, however, the preweaning situation, which was regularly observed, is an unexpected phenomenon. (4) Maltase and glucoamylase did not display any marked qualitative or quantitative modifications either along the villus-crypt axis or during the period of postnatal development studied. Evidence is given from the present data that each brush-border enzyme investigated has a specific developmental pattern.
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PMID:Developmental pattern of rat intestinal brush-border enzymic proteins along the villus--crypt axis. 10 86

This investigation deals with the histochemical, biochemical and electron microscopical development of the postnatal epithelium in the small intestine of guinea-pigs. Immediately after birth the enterocytes of the whole small intestine are rich in glycogen. Within 48 hours the glycogen in broken down by intralysosomal digestion and glycogenolysis or disappears from the villus epithelium by extrusion of the absorptive cells. The first loss of glycogen occurs in the jejunum; at the latest it leaves the lining epithelium of the ileum so that a proxoim-distal gradient exists. Afterwards for maximal 14 days fat ist taken up from the mother's milk only by the enterocytes of the jejunum without any signs of endocytosis; the bigger part of the fat leaves the cells by exocytosis and enters the intercellular space. Most of the lipid reaches the lymphatics or is absorbed by marcophages; only small amounts are found in the blood capillaries. The number of the enterocytes engaged in the absorption and passage of fat depends on its quantity in the lumen of the small intestine. During the first days of life everywhere in the small intestine the ultrastructure of the enterocytes is characterized by 2 types of mitochondria (large and small ones with different internal structure). Furthermore in the ileum the absorptive cells contain more lysosomes and a more extensive inframicrovillous membrane system than in jejunum. The membrane system consists of aggregated tubules, vacuoles and vesicles; they are situated below the microvilli and sometimes communicate with the lumen of the gut. The big mitochondria are broken down in the lysosomes or appear in the lumen of the small bowel following extrusion of the enterocytes. The lysosomes are involved in autophagic (digestion of glycogen and cell organelles) as well as in autophagic processes (hydrolysis of molecules from the mother's milk and foreign food). These substances are probably incorporated by means of the inframicrovillous membrane system. With respect to the microvillous hydrolases (lactase, alpha-D-glucosidases, peptidases, alkaline phosphatase) histochemical and biochemical assays were carried out with the same artificial substrate. The results depend on the method employed and the enzyme investigated. Using histochemical techniques and indolyl, naphthly, naphthol AS or naphthylamine derivatives as substrates the activity of peptidases and alkaline phosphatase correspond to that in adult guinea-pigs already at the time of birth; alpha-D-glucosidases (glucoamylase, saccharaseisomaltase) become mature at the end of the first, and the development of lactase is finished after the second week of life. For the biochemical investigations (fluorometric measurements of naphthol and naphthylamine) of microvillous enzymes with naphthyl and naphthylamine substrates a new technique of homogenisation using freeze-dried cryostate sections is successfully employed...
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PMID:[Postnatal development of the epithelium of the small intestine of guinea-pigs (author's transl)]. 21 41

The postition of a number of human intestine brush border membrane enzyme activities in polyacrylamide gels after electrophoresis has been determined. These activities are, in order from the origin, maltase/glucoamylase, lactase/phlorizin hydrolase, maltase/sucrase/isomaltase, enteropeptidase, trehalase and gamma-glutamyl-transferase. Leucylnaphthylamide hydrolyzing activity was inactivated by sodium dodecylsulfate and its position was not determined. The positions of the activities have been correlated with the positions of protein bands previously determined. One such band situated between enteropeptidase and alkaline phosphatase has not been identified.
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PMID:Enzymes of the human intestinal brush border membrane. Identification after gel electrophoretic separation. 23 25

1. Intestinal brush border membrane vesicles have been isolated form Rana catesbeiana tadpole. 2. Electron microscopy of brush border membrane vesicles demonstrates a fairly homogenous preparation of vesicles, some of them still containing electron dense material. 3. The dense vesicles probably comprise both microvillus core and membrane. 4. Negative staining of vesicles reveals the presence of knob-like structures (particles) covering the outer surface of the membrane. 5. The membranous fraction is characterized by a high specific activity of alkaline phosphatase, trehalase, glucoamylase, maltase and gamma-glutamyltranspeptidase.
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PMID:Amphibian intestinal brush border membranes-I. Isolation from Rana catesbeiana tadpole. 31 43

The addition of 10 mM ammonium sulfate to sporulation medium noncoordinately blocked the increases in protease C, protease B, alpha-mannosidase, and 1,4-amyloglucosidase activities which occur during normal sporulation of Saccharomyces cerevisiae, but had only a minor effect on the 10-fold increase in alkaline phosphatase activity.
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PMID:Effect of ammonium ions on activity of hydrolytic enzymes during sporulation of yeast. 37 25

Advances in the study of membrane digestion are described which relate to techniques for the separation of the apical glycocalyx and the study of the distribution of enzymes between the latter and the cell membrane. The regulatory properties of brush border enzymes have been demonstrated. Membrane digestion by pancreatic enzymes adsorbed on the mucosal surface and by enteric enzymes predominates in early development, whereas intraluminal digestion develops during the transition to definitive (adult) nutrition. Substrate and other, non-substrate factors are involved in the regulation of intraluminal and membrane digestion in ontogeny. The importance of lipid components of the diet for the maintenance of proximal-distal gradients of enzyme activity in the small intestine during the transition from milk to adult nutrition is discussed. At this period of development hydrocortisone affects both the synthesis of enzymes and their incorporation into the enterocyte membrane. The inducibility of different enzymes is not identical. The hypothesis has been proposed that stress is one of the factors inducing or repressing the synthesis of brush border enzymes. These effects are mediated through the hypothalamus, adrenals, hypophysis and thyroid. The experimental findings demonstrate that various stressors are responsible for the induction of sucrase, maltases, gamma-amylase, peptidases and alkaline phosphatase, and for the repression of lactase in suckling rats.
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PMID:Membrane digestion and nutrient assimilation in early development. 39 34

1. The proteins of the intestinal microvillus membrane have been studied during post-natal development in the rat (days 12--37). 2. In suckling animals (up to age 20 days), the majority of alkaline phosphatase, glucoamylase and lactase activities in the distal half of the intestine were located in the supernatant fraction (100000 X g, 60 min). These enzymes were attached to the membrane from the proximal intestine at all ages. 3. Alkaline phosphatase, maltase and lactase activities in the supernatant fractions chromatographed in Sephadex G-200 in positions similar to the corresponding membrane enzyme. Corresponding activities for lysosomal counter-parts of maltase and lactase present in the supernatant fraction chromatographed differently. Moreover, pH optimum of the soluble enzymes was 9.2 for phosphatase and 5.5--6.0 for glycoamylase and lactase. The soluble lactase and alkaline phosphatase were inhibited minimally by p-chloromercuribenzoate, and sodium fluoride respectively. L-Phenylalanine (20 mM) did inhibit the soluble phosphatase by 90%. Thus, the soluble enzymes are not mainly of the lysosomal origin, but have characteristics of membrane-bound enzymes. 4. Polyacrylamide gel electrophoresis in sodium dodecyl sulfate revealed 18 protein bands which were present in adult membranes. Two other proteins were unique for membranes of distal intestine in suckling rats. The proteins corresponding to known enzyme activity changed as expected with age (e.g. sucrase, maltase increased, lactase decreased). Most of the other proteins were also altered in amount during development. Thus, the changes in the microvillus membrane during development in the rat are not limited to specific enzymes.
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PMID:Development of intestinal brush border membrane proteins in the rat. 41 9

It is shown that certain key enzymes in membranous digestion (alkaline phosphatase, peptidase, gamma-amylase) are allosteric and ensure the autoregulation and the homoeostasis of the final stages of hydrolysis and of the initial stages of nutrient transport. This mechanism was evidenced not only in vertebrates (mammals, birds, fishes), but also in invertebrates (drosophilae). The comparison of the triton and trypsin forms of the enzymes permitted to locate centres of regulation in the hydrophobic parts of amphipathetic enzymes (as illustrated by the examples of alkaline phosphatase and gamma-amylase of of the rat and of the drosophila). A considerable variability of the regulatory characteristics of the enzymes under investigation was demonstrated in the different varieties of drosophila. The authors present a hypothesis on the role of the regulatory properties of digestive enzymes in the physiology and the pathology of the digestive and transport systems of the small intestine.
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PMID:[Regulatory properties of the intestinal enzymes of higher and lower animals as an adaptation mechanism in digestion and absorption]. 48 66


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