Gene/Protein Disease Symptom Drug Enzyme Compound
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Query: EC:3.2.1.26 (invertase)
 4,927 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

Rats eating a diet containing casein hydrolysate (10% wt/wt)(diet 3) instead of whole casein (diet 1) exhibited increased tolerance to nine consecutive daily injections of 15 mg/kg of 5-fluorouracil (5-FU). The relative nutritional efficiency of diet 3 was significantly higher during 5-FU treatment. Serum albumin levels measured after 5-FU treatment dropped by only 2.7% in diet 3 groups and by 13.5% in diet 1 groups. Serum albumin values for rats on the control diet (Purina lab chow) were comparable to those on diet 1. No 5-FU-related mortality was observed in any of the groups. Intestinal brush border enzymes were determined in a group of rats on diet 1. At the end of 5-FU treatment statistically significant changes were observed: sucrase dropped to 30% of control and leucylnaphthylamide-hydrolyzing activity dropped to 19% of control. The activity of gamma-glutamyltransferase did not change significantly. It is postulated that under these circumstances a mixture with a prevalence of free amino acids (casein hydrolysate) could be more readily absorbed than a corresponding mixture containing a larger proportion of oligopeptides.
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PMID:Use of an elemental diet in animals during treatment with 5-fluorouracil (NSC-19893). 1 89

Leucine beta-naphthylamidase associated with the microvilli membranes of rabbit small intestine was solubilized with papain [EC 3.4.22.2] and purified by Sephadex G-200 gel filtration, DEAE-cellulose column chromatography, passage through a column of Sepharose 4B coupled with anti-sucrase antibodies and preparative disc electrophoresis in polyacrylamide gel. The purified enzyme was homogeneous on ultracentrifugation and disc electrophoresis, but a double immunodiffusion test showed the presence of a minor component which was probably denatured enzyme. The molecular weight of the purified enzyme was estimated to be 225,000 by Sephadex G-200 gel filtration and the sedimentation coefficient (S-0-20, w) was found to be 6.90S. Purified enzyme required bovine serum albumin for maximal activity, perhaps for its protection from autodigestion. It hydrolyzed, in addition to L-leucine beta-naphthylamide, various L-amino acid beta-naphthylamides and dipeptides with a free alpha-amino group, but did not hydrolyze benzoyl-L-arginine beta-naphthylamide. Therefore, the purified enzyme is an aminopeptidase. Hg-2+ and Cu-2+ ions strongly inhibited the enzyme activity, but other metal ions and EDTA showed no or only slight effect. N-Ethylmaleimide exhibited a weak inhibition. Purified enzyme had an optimal pH and Km value for leucine beta-naphthylamide similar to those of enzymes from other sources. Antibodies against the purified enzyme were raised in guinea pigs. The antibodies obtained were found by double immunodiffusion to be specific for the enzyme. They precipitated the enzyme quantitatively and partially inhibited the enzyme activity.
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PMID:Purification and properties of leucine beta-naphthylamidase from rabbit small-intestinal mucosal cells. 23 93

Yeast invertase was co-reticulated with glutaraldehyde to bovine serum albumin to give a soluble bound enzyme that was immobilized as a tightly adhering layer on the active surface of an ultrafiltration membrane. The Michaelis constant and stability of this immobilized-enzyme system are compared with those of the enzyme either in the native form or immobilized as a dynamically formed gel layer on an ultrafiltration membrane, as previously described by us [Drioli, Gianfreda, Palescandolo & Scardi (1975) Biotechnol, Bioeng, 17, 1365-1367].
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PMID:Preparation and properties of co-reticulated invertase supported by an ultrafiltration membrane. 58 66

We compared the receptor-mediated endocytosis for galactose and mannose exposing ligands in primary cultures of hepatocytes from newborn and adult rats. The endocytic pathway was revealed ultrastructurally using colloidal gold particles coupled to lactosylated bovine serum albumin and invertase. The binding activity on the cell surfaces is observed by keeping the cells at 4 degrees C. For both ligands used, the binding capacity for hepatocytes from adult rats was greater than for neonatal cultured cells. Increasing the temperature to 37 degrees C, we observed that the protein-gold complexes entered the intracellular endocytic organelles. Within 5-15 min, the marker was confined in vesicles close to the cell surface and in the endosome, while after 60 min, the marker is found in lysosome-like compartments. We found that the process of endocytosis is similar for galactose and mannose exposing ligands. The organelles involved in the process of endocytosis in newborn cultured hepatocytes are not different in shape from those of cultured cells of adult rats, but the process of internalization is slower.
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PMID:Receptor-mediated endocytosis of galactose and mannose exposing ligands: an electron microscopic study on adult and neonatal cultured rat hepatocytes. 131 31

We have fused a cDNA gene encoding mature human serum albumin (HSA) to several secretory leader-encoding sequences. The hybrid genes were cloned into an episomal vector under the control of several yeast promoters and then introduced into yeast cells. The GAL1 promoter in combination with either the native HSA pre-sequence or a modified HSA pre-sequence gave the highest production of immunoreactive HSA, 90 mg/liter being reached in a shake flask culture. The invertase pre-sequence, the mating factor alpha 1 prepro-sequence, and the modified HSA pre-sequence directed accurate processing. In contrast, the chicken lysozyme pre-sequence and the native HSA pre-sequence directed incorrect processing. Episomal vectors were unstable within the host cells under non-selective culture conditions. To improve the plasmid stability, the hybrid genes were incorporated into an integrative vector. Transformants carrying multicopies of the plasmid integrated at the LEU2 locus stably secreted HSA. The highest yield of 65 mg/liter in a shake flask culture was obtained with the combination of the yeast glyceraldehyde-3-phosphate dehydrogenase promoter and the modified HSA pre-sequence. By constructing transformed strains containing multicopies of plasmids integrated at both the chromosome LEU2 and HIS4 loci, we have obtained a stable strain that continuously secretes as much as 85 mg HSA per liter of culture medium.
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PMID:Secretory expression of the human serum albumin gene in the yeast, Saccharomyces cerevisiae. 193 15

Free fatty acids can enter the enterocyte via the apical or basolateral plasma membrane. We have used the Caco-2 intestinal cell line to examine the polarity of free fatty acid uptake and metabolism in the enterocyte. Differentiated Caco-2 cells form polarized monolayers with tight junctions, and express the small intestine-specific enzymes sucrase and alkaline phosphatase. Cells were grown on permeable polycarbonate Transwell filters, thus allowing separate access to the apical and basolateral compartments. Total uptake of [3H]palmitate bound to bovine serum albumin (palmitate-BSA 4:1) was twofold higher (P less than 0.05 or less) at the apical surface than at the basolateral surface. The relative apical and basolateral membrane surface areas of the Caco-2 cells, as measured by partition of the fluorophore trimethylammonium-diphenylhexatriene TMA-DPH), was found to be 1:3. Thus, apical fatty acid uptake was sixfold higher than basolateral uptake per unit surface area. Analysis of metabolites after incubation with submicellar concentrations of [3H]palmitate showed that the triacylglycerol to phospholipid (TG:PL) ratio was higher for fatty acid added to the apical as compared to the basolateral compartment (20% at 60 min, P less than 0.025). Little fatty acid oxidation was observed. Preincubation with albumin-bound palmitate, alone or with monoolein, increased the incorporation of both apical and basolateral free fatty acids into TG. The results suggest that the net uptake of long-chain free fatty acids across the apical plasma membrane is greater than uptake across the basolateral membrane. In addition, a small increase in the TG:PL ratio for apically, compared to basolaterally, added free fatty acids suggests that polarity of metabolism occurs to a limited extent in Caco-2 enterocytes.
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PMID:Fatty acid uptake and metabolism in a human intestinal cell line (Caco-2): comparison of apical and basolateral incubation. 206 64

We immobilized human milk galactosyltransferase covalently to CNBr- and tresylchloride-activated Sepharose. The enzyme was also immobilized non-covalently to Concanavalin A-Sepharose and to monoclonal anti-galactosyltransferase antibodies which were bound via their Fc-fragment to Protein G-Sepharose. With the covalent methods, up to 72% of the enzyme could be bound to the carrier, but more than 90% of the specific activity was lost. In contrast, non-covalent immobilization yielded only about 50% immobilization efficiency, but 21% and 25% of specific activity, respectively, could be recovered. The stability of immobilized galactosyltransferase as compared to native enzyme was considerably increased: at room temperature, 55% of initial immobilized activity was lost after 65 hours compared to 95% of loss of soluble enzyme activity. Immobilized galactosyltransferase was then used for continuous galactosylation of the glycoproteins ovalbumin, endo H-treated yeast invertase and bovine serum albumin-N-acetylglucosamine in a "slurry" reactor. 55%, 35% and 25%, respectively, of all acceptor sites on these glycoproteins could be galactosylated by this method.
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PMID:Immobilization of galactosyltransferase and continuous galactosylation of glycoproteins in a reactor. 213 55

To investigate whether intestinal resection accelerates mucosal maturation in suckling rats, macromolecular absorption, sucrase and lactase activity, RNA/DNA ratios, and intestinal morphology were determined 5 days after partial small intestinal resection or intestinal transection in 15-day-old rats. Villous height and crypt depth, lactase and sucrase activity, and RNA/DNA ratios were significantly increased in remaining intestine in animals that underwent surgery. These animals, together with normal control animals, were also gavaged with 100 mg bovine serum albumin, and serum levels were determined after 2.5 h. Mean serum levels of bovine serum albumin were 0.135 +/- 0.034 micrograms/ml/cm of residual intestine after transsection, 0.257 +/- 0.078 micrograms/ml/cm after resection, and 0.404 +/- 0.030 micrograms/ml/cm in controls. These studies demonstrate that intestinal resection during the suckling period of the infant rat results in several morphologic and physiologic changes that resemble precocious maturation of the small intestine.
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PMID:Intestinal resection in the neonatal rat: stimulus for precocious intestinal maturation. 241 4

Six-week-old rats subjected to prenatal and postnatal dietary restriction (maternal and weanling intake = 50% that of controls) were studied. Compared with controls, malnourished rats not only had reduced body (78 +/- 12 vs 187 +/- 21 g) and organ weights (small intestine: 4.51 +/- 0.46 vs 9.89 +/- 0.61 g; colon: 0.75 +/- 0.08 vs 1.77 +/- 0.18 g; liver: 2.75 +/- 0.34 vs 9.13 +/- 1.33 g; pancreas: 0.78 +/- 0.14 vs 1.67 +/- 0.49 g) but also decreased body weight-length ratios (6.5 +/- 0.3 vs 10.8 +/- 1.4 g/cm) and serum albumin levels. The small intestinal mucosa was hypotrophic (protein-DNA ratio: 5.02 +/- 1.43 vs 8.82 +/- 0.68, malnourished vs controls, respectively) with reduced mucosal thickness, villus height, and crypt depth. Specific activities of lactase, maltase, and sucrase were diminished (53%, 66%, 54% of control values, respectively). Colonic mucosa was hypoplastic with decreased mucosal thickness and crypt depth. Liver and pancreas were both hypotrophic and hypoplastic. The findings suggest that, in contrast to colonic mucosa, pancreas, and liver, the small intestinal mucosa maintained cell number during prolonged prenatal and postnatal malnutrition.
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PMID:Biochemical and morphological changes in the digestive tract of rats after prenatal and postnatal malnutrition. 250 4

Experiments in order to induce food allergy were carried out in guinea pigs. The sensitization with egg albumin, pasteurized cow milk and bovine serum albumin provoked anaphylactic shock. The passive cutaneous anaphylaxis, serum antibodies, liver cytochrome P-450 concentration and the anaphylactic shock were determined. Some correlation between the mortality, anaphylactic antibodies and cytochrome P-450 monooxygenase system was established. The morphology of the jejunal mucosa, the activities of the 5 disaccharidases, the number of immunoglobulin secreting cells (Ig SC) and the mastocytes were investigated in 35 patients with food allergy. Normal mucosa was found in 28 cases as well as a significant decrease of the lactase, sucrase and trehalase activities. An increase of IgM and IgG secreting cells and of mastocytes, different electron microscopic changes in the enterocytes (an increased number of lysosomes, appearance of vesicles in cytoplasma, shortening, enlargement and uneven distribution of microvilli) as well as symptoms of functional activity in the plasmocytes and some others were also revealed. The experimental model obtained is similar to that one in humans according to the enteral way of sensitization the high selectivity of the allergic reaction which is of reagin type as the immunoglobulin changes are involved.
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PMID:Immunological and radioimmunological studies in food allergy. 295 46


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