Gene/Protein Disease Symptom Drug Enzyme Compound
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Query: EC:3.2.1.108 (lactase)
 2,133 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

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

1. Lactose 6'-O-sulphate, N-acetylneuraminyl-(alpha 2 leads to 3)-D-lactose 6'-O-sulphate, N-acetylneuraminyl ?-O-sulphate-(alpha 2 leads to 3)-D-lactose 6'0-O-sulphate, N-acetylneuraminyl ?-O-sulphate-(alpha 2 leads to 6)-D-lactose and N-acetylneuraminyl-(alpha 2 leads to 3)- and -(alpha 2 leads to 6))-lactose 6'-O-sulphate were prepared by chemical sulphation of lactose, N-acetylneuraminyl-lactose and tis isomers by using pyridine-SO3 reagent. 2. Significant kinetic differences were observed in the enzymic hydrolysis of the sulphated derivatives compared with unsubstituted substrates. 3. In the case of reactions catalysed by rat liver lysosomal and Clostridium perfringens neuraminidases (EC 3.2.1.18), the presence of an O-sulphate group in the N-acetylneuraminyl moiety affected the reaction by decreasing the Km and the Vmax, its presence in the galactosyl moiety affected the reaction by decreasing the Km and increasing the Vmax. and its presence in both N-acetylneuraminyl and galactosyl moieties decreased the Km and the Vmax. of the reaction. 4. Mixed-substrate reaction kinetic data indicated competition between the sulphated and unsubstituted substrates for the same active sites on the neuraminidase molecule. 5. Lactose 6'-O-sulphate neither behaved as a substrate nor acted as an inhibitor with respect to unsubstituted lactose and p-nitrophenyl beta-D-galactopyranoside when tested with lactase of suckling rat intestine and Escherichia coli beta-D-galactosidase (EC 3.2.1.23). 6. Preliminary investigation also indicated that, whereas glucose 6-O-sulphate and glucose 3-O-sulphate were were neither substrate nor inhibitor of glucose oxidase (EC 1.1.3.4), galactose 6-O-sulphate was oxidized half as fast as unsubstituted galactose by galactose dehydrogenase (EC 1.1.1.48).
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PMID:Effect of O-sulphate groups in lactose and N-acetylneuraminyl-lactose on their enzymic hydrolysis. 22 64

The infectivity of a bovine rotavirus was enhanced 140-, 8-, and 3-fold, respectively, by trypsin, protease, and lactase. Ficin, carboxypeptidases A and B, lysozyme, and beta-galactosidase had little effect on the infectivity. Chymotrypsin caused a threefold decrease in the infectivity. Trypsin acts directly on the rotavirus and not on the host cell.
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PMID:Effect of enzymes on rotavirus infectivity. 22 17

Two studies were conducted to establish the effects of dietary lactose supplied from dried whey on the lactase activity in the contents of the small intestine and cecum as well as the mucosa of the small intestine. In the first study, feeding 0, 10, 25, or 40% dried whey for 120 days did not alter the mucosal lactase specific activity (mumoles galactose released/mg protein) in the duodenum, upper jejunum, or lower ileum. In the second study, total lactase activity in the small intestine was estimated from the total activity found in 10-cm segments of each meter of small intestine. Feeding a diet containing 40% whey continuously from weaning at 5 weeks of age or from 12 weeks of age did not alter the total lactase activity of pigs killed at 21 weeks of age. Dietary lactose tended to increase the lactase activity in the contents of the cecum and small intestine, but the increases were not always statistically significant. In the second study, Chester White pigs had approximately threefold greater mucosal lactase activities than that of Hampshires. These two breeds may be suitable models for detailed studies into the relationships between lactase deficiency and lactose intolerance.
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PMID:Effects of diets containing dried whey on the lactase activity of the small intestinal mucosa and the contents of the small intestine and cecum of the pig. 23 67

Physiological bases of digestion and absorption of carbohydrates are reviewed, as a preliminary step, in order to draw a general scheme of its patholophysiology. Clasification of different types of carbohydrate malabsorption is presented. Various exploration methods are discussed in terms of autors' own experiences. Relationship between a sugar screening test, faecal lactic acid contents and a simplified lactose tolerance test, is described in detail. Systematic diagnoses of these diseases are established. Different clinical pictures are reviewed. It is not yet well defined if a starch malabsorption can be caused by either a primary or secondary duodenal amylase deficiency. The clinical forms of congenital sucrose-isomaltose intolerance may be more attenuated than its classical form; incertain cases, secondary sucrose intolerance may also be present due to mucosa anatomic lesions. Maltose malabsorption has no clinical implications. As compared to other alpha-glycosidades, the trehalase activity has been not more affected by not using trehalose in feeding. Primary congenital lactase deficiency is not frequent, whereas secondary forms as much more usual and appear, in primary malabsorption syndromes and in the coeliac disease, very often along with clinical tolerance to lactose. In Spain, lactose nonabsorbers in 16.5% for adults 11.2% for adolescents and 18.3% for children, meaning, that it is being favored by environmental factors in the latter. The unspecified sugar malabsorption during the child's first year is still the most frequent cause of carbohydrate intolerance in children and, although certain progress has been achieved in its diagnosis and therapy, its pathogenic mechanism is not satisfactorily known yet.
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PMID:[Malabsorption of carbohydrates in children (author's transl)]. 23 44

1. Intracellular distribution of three types of beta-galactosidases (beta-D-galactoside galactohydrolase EC 3.2.1.12) i.e. hetero beta-galactosidase, lactase and acid beta-galactosidase, was studied by examining the properties of subcellular fractions isolated by a systematic fractionation of mucosal cells of the small intestine of the hog. Localization of hetero beta-galactosidase in cytosol could be shown. 2. Localization of lactase in the brush borders was shown by analyzing the purified brush borders prepared separately. 3. To domonstrate the lysosomal localization of acid belta-galactosidase, lysosomes were purified separately and their extract was chromatographed on a hydroxylapatite column. The activities of various enzymes in the purified lysosomes as well as in the intermediary fractions obtained during lysosome purification and the pattern of the hydroxylapatite chromatography led us to conclude that acid beta-galactosidase is a lysosomal enzyme.
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PMID:Intracellular distribution of beta-galactosidases in mucosal cells from hog small intestine. 23 31

The activities of rat intestinal enzymes, sucrase, lactase, maltase, trehalase, gamma-glutamyltransferase, leucylnaphthylamide-hydrolyzing activity, and the transport system for glucose follow diurnal rhythms on ad libitum and restricted feeding regimes. In response to 6 days of restricted feeding, food available between 1400 and 1800 Eastern Standard Time, all rhythms shifted in time and the daily levels of activities were changed. Alkaline phosphatase activity followed a diurnal rhythm only in restricted fed animals. In restricted fed rats several activity patterns were observed, some with short periods of maximum activity, 3 h or less, and some with plateaus of maximum activity, 5-9 h long. In respect to the time of day of the synchronizer, sucrase peaked before feeding, glucose transport peaked during feeding, alkaline phosphatase peaked after feeding, and the other enzymes had higher levels of activity before, during and after feeding. The effect of restricted feeding on the daily activity levels were: a decrease in leucylnaphthylamide-hydrolyzing activity, no change in alkaline phosphatase, and increases in the others. These enzyme and transport systems exhibit a large amount of individual regulation or control as reflected by the lack of a uniform activity pattern and response to the synchronizer, and the variation in direction and magnitude of the adaptations to restricted feeding.
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PMID:Effect of changes in feeding schedule on the diurnal rhythms and daily activity levels of intestinal brush border enzymes and transport systems. 24 Apr 40

A brush-border-specific antiserum was raised in rabbits, with Triton X-100-solubilized brush border proteins from pig intestine being used as antigens. The antiserum was used in immunoelectrophoretic studies of brush border proteins solubilized with Triton X-100. Five immunoprecipitates were obtained which corresponded to microsomal aminopeptidase (EC 3.4.11.2), asparate aminopeptidase (EC 3.4.11.7), lactase (beta-galactosidase, EC 3.2.1.23), maltase (exo-1,4-alpha-glucosidase, EC 3.2.1.3) and sucrase-isomaltase (sucrose alpha-glucohydrolase, EC 3.2.1.48). A faint immunoprecipitate was also found for the glycylprolyl dipeptidyl peptidase (EC 3.4.14.-). The brush border proteins were solubilized on a large scale from a brush border membrane preparation by the use of Triton X-100; the peptidases obtained were homogeneous in size and had hydrophobic properties. By chromatography on columns of concanavalin A-Sepharose, hydroxyapatite, Ultrogel AcA 34, DEAE-cellulose and immunosorbent, gamma-glutamyl transpeptidase (gamma-glutamyl transferase, EC 2.3.2.2) and microsomal aminopeptidase were each isolated in separate fractions. Glycylprolyl dipeptidyl peptidase and asparate aminopeptidase were obtained in another fraction. Immunoelectrophoretic, inhibitor and chromatographic studies showed that the intestinal brush border peptidases are similar to the corresponding particulate peptidases obtained from other organs.
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PMID:Intestinal brush border peptidases. 24 83

Histochemical examination of aspiration biopsy specimens of the duodenum in 8 healthy volunteers and 23 patients with various gastrointestinal disorders revealed no characteristic abnormality except for a rather frequent absence of the activity of disacharidases especially of lactase. A distinct difference of disacharidase was established between the duodenum and the jejunum in some individuals. A systematic study of different levels of the upper gastrointestinal tract established the fact that the activity of brush border enzymes of enterocytes starts to appear in individually different parts of the duodenum and sometimes even as low as in the jejunum. The distribution of lysosomal enzymes and the activity of dehydrogenases display differences as well. Consequently specimens from different parts of the duodenal and jejunal mucosa are not equivalent and cannot be used alternatively for diagnostic purposes. Biopsies of duodenal mucosa are not adequate for the diagnosis of the malabsorption syndrome.
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PMID:Histochemistry of the human duodenal mucosa with special reference to the gradient of activities of the brush border enzymes. 29 9

A controlled double-blind biometric and an open clinical trial were conducted to determine the therapeutic effectiveness of a new equal-dose w/w association of amoxicillin and flucloxacillin. The following conclusions were drawn. Both antibiotics were present in high serum levels; those of flucloxacillin were higher and more persistent. Analysis of variance on 89 patients pointed to the superiority of the association by comparison with amoxicillin alone. The clinical study made it clear that the broad and complementary spectrum of the association, its synergy, absence of toxicity and good gastric tolerance make it a valuable and effective therapeutic aid, also in presence of germs that produce beta-lactase.
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PMID:[Pharmacokinetic and clinical research on a new antibiotic combination (amoxicillin and flucloxacillin in equivalent-weight dose)]. 32 92


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