Gene/Protein Disease Symptom Drug Enzyme Compound
Pivot Concepts: Gene/Protein Disease Symptom Drug Enzyme Compound   Target Concepts: Gene/Protein Disease Symptom Drug Enzyme Compound

---

Query: EC:3.2.1.26 (invertase)
4,927 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

The effect on rats of oral doses (38.66 mM/kg body wt) of propane-1,2-diol (PD) administered daily for 10 (Group 1), 20 (Group 2), and 30 days (Group 3) was investigated. Weight gain was initially retarded (P less than 0.05) in Group 1, but was later reversed and elevated significantly (P less than 0.05) in Groups 2 and 3 as compared with their respective controls receiving an equal volume of saline. PD showed a tendency toward enhancing the activities of various enzymes involved in terminal digestion, with the significant effect exerted in few groups on sucrase (P less than 0.05), lactase (P less than 0.05), and gamma-glutamyl transpeptidase (P less than 0.05) when compared with the respective controls. Absorption of D-glucose, glycine, L-aspartic acid, L-lysine, and calcium was elevated and was especially significant in Groups 2 and 3 (P less than 0.001). The structural integrity of the jejunal surface was retained for the most part. A similar examination of the effects of PD was also carried out in vitro to ascertain whether PD itself or its metabolites are involved in its action. The in vitro effects of propane-1,2-diol were compared with those of the more toxic compound propane-1,3-diol. The former exerted greater inhibitory action on the activities of the disaccharidases. The degree of inhibition was in the order sucrase much greater than lactase greater than maltase. The kinetic data revealed that inhibition by 1,2-diol in native and detergent solubilized sucrase is noncompetitive, with Ki values in the range of 0.35-0.41 M. The two diols did not alter the nutrient transport in the brush border membrane vesicles. The present work on rats indicates that PD may influence the intestinal digestive and absorptive functions in vivo and that this in vivo effect of PD is different from that observed in vitro suggesting that the nutritional and toxicological effect of PD may be mediated by different mechanisms.
...
PMID:The effect of propane-diols on the intestinal uptake of nutrients and brush border membrane enzymes in the rat. 188 24

We have investigated different leader sequences for their ability to direct the efficient secretion of human epidermal growth factor (hEGF) from Saccharomyces cerevisiae. We designed a consensus signal sequence which directs secretion of hEGF from yeast as efficiently as the yeast invertase signal sequence. However, secretion is increased over fivefold by the introduction, after the signal sequence, of a synthetic 19-amino acid (aa) pro-sequence containing a cleavage recognition site for the KEX2 protease. Even in the absence of an Asn-linked glycosylation site, secretion of hEGF using the synthetic prepro-leader was as efficient as that directed by the alpha-factor leader. The role of the KEX2 protease cleavage site was investigated by mutation of the yeast alpha-factor KEX2 site (cleavage after Lys-Arg). Cleavage was obtained with the following order of efficiency, Lys-Arg greater than Pro-Arg greater than Asp-Arg, although the sequence context was also found to affect efficiency.
...
PMID:Secretion of human epidermal growth factor from Saccharomyces cerevisiae using synthetic leader sequences. 193 55

The SNF1 gene of Saccharomyces cerevisiae encodes a protein-serine/threonine kinase that is required for derepression of gene expression in response to glucose limitation. We present evidence that the protein kinase activity is essential for SNF1 function: substitution of Arg for Lys in the putative ATP-binding site results in a mutant phenotype. A polyhistidine tract near the N terminus was found to be dispensable. Deletion of the large region C terminal to the kinase domain only partially impaired SNF1 function, causing expression of invertase to be somewhat reduced but still glucose repressible. The function of the SNF4 gene, another component of the regulatory system, was required for maximal in vitro activity of the SNF1 protein kinase. Increased SNF1 gene dosage partially alleviated the requirement for SNF4. C-terminal deletions of SNF1 also reduced dependence on SNF4. Our findings suggest that SNF4 acts as a positive effector of the kinase but does not serve a regulatory function in signaling glucose availability.
...
PMID:Mutational analysis of the Saccharomyces cerevisiae SNF1 protein kinase and evidence for functional interaction with the SNF4 protein. 255 46

An experiment was done to determine maltase, sucrase, isomaltase, and trehalase activities in mucosa of different segments of small intestines of young turkeys as influenced by age and diet. Two-day-old poults were fed diets containing no added fat [44.6% starch, 2.2% ether extract by weight (HC)], 10% tallow (T), or 10% corn oil [(CO) 29.0% starch, 10.9% ether extract]. Diets HC, T, and CO were calculated to contain 2,705, 3,083, and 3,196 kcal ME/kg, respectively, and constant protein, TSAA, and lysine:ME ratios were maintained. Appreciable maltase and isomaltase specific activities (micromoles of substrate hydrolyzed per milligram protein per hour) were observed in 2-day-old poults, and activities of these enzymes increased in poults fed the HC diet through 7 and 14 days, respectively. At 2 days, specific activity of sucrase was low, and trehalase activity was not detected. Sucrase activity increased steadily through 28 days of age in poults fed the HC diet. Trehalase activity was detected at 7 days of age and reached a maximum by Day 21 after hatch. By Day 28, trehalase activity had disappeared from all segments except for the proximal jejunum. In 28-day-old poults fed the HC diet, specific activities of all disaccharidases were greatest in the jejunal segments; i.e., 21, 1.06, 7.24, and .034 mumol/mg protein/h for maltase, sucrase, isomaltase, and trehalase, respectively, in the proximal jejunum. Poults fed the T or CO diets had significantly lower disaccharidase activities than did those fed the HC diet, beginning at 7 days of age. Changes in specific activities of disaccharidases as related to age or diet or both were not always parallel, suggesting that each enzyme may be regulated by or affected by diet in a partly independent way.
...
PMID:Intestinal disaccharidases of young turkeys: temporal development and influence of diet composition. 264 74

We have evaluated the participation of mannose receptors on the surface of stimulated macrophages in the phagocytosis of Candida albicans in vitro. A dose-dependent 8.6 to 88.3% reduction of phagocytosis was observed in the presence of 0.5 to 5.0 mg/ml of the mannose-rich glycoprotein invertase (either native or denatured) in the incubation medium. Macrophages plated onto substrates coated with poly-L-lysine-mannan also showed a 99% reduction of phagocytic activity toward Candida albicans, but phagocytosis of IgG-coated erythrocytes was not inhibited under the same conditions. These results indicate that mannose receptors are involved in one of the initial steps of phagocytosis of Candida albicans by macrophages.
...
PMID:Participation of mannose receptors on the surface of stimulated macrophages in the phagocytosis of glutaraldehyde-fixed Candida albicans, in vitro. 270 Apr 33

1. In the newborn pig it appears that only prenatally produced enterocytes are capable of absorbing large amounts of protein. 2. The ability of the small intestine to transport sodium, lysine, lysine containing dipeptides and glucose declines markedly during the first week of post natal life. 3. Dexamethosone causes a doubling of the sodium dependent portion of alanine uptake. 4. EGF given between days three and six of postnatal life increases sucrase and maltase activity in the distal region of the small intestine. 5. Weaning induced problems are probably not due to direct inhibition of transport properties.
...
PMID:Postnatal development of transport function in the pig intestine. 290 64

Adult female Sprague-Dawley rats were fed isocaloric semipurified diets containing a high content of either polyunsaturated (P) or saturated (S) fatty acids; these diets were nutritionally adequate, providing for all known essential nutrient requirements. On day 3 after beginning S or P, one group of animals was exposed to a single 6-Gy dose of abdominal radiation, and the other half was sham irradiated. S or P diets were continued for a further 14 days. Brush-border membrane purification and sucrase-specific activities were unaffected by diet or by abdominal irradiation. In rats fed P, irradiation was associated with an increase in jejunal brush-border membrane total phospholipid and the ratio of phospholipid to cholesterol; these changes were not observed in animals fed S. In irradiated rats, ileal brush-border membrane phospholipid per cholesterol was high in animals fed S compared with P. In irradiated animals fed P, there was reduced jejunal and ileal uptake of several medium- and long-chain saturated and unsaturated fatty acids and cholesterol, and the ileal uptake of higher concentrations of glucose was reduced in irradiated animals fed P. In contrast, lipid uptake was similar in control and irradiated animals fed S except for cholesterol uptake, which was reduced. Ileal uptake of higher concentrations of glucose was increased in irradiated animals fed S. Quantitative autoradiography failed to demonstrate any change in the distribution of leucine or lysine transport sites along the villus 1 or 2 wk after abdominal irradiation or in response to feeding S or P. Also, these differences in transport achieved by feeding S to radiated animals were not explained by variations in the animals' food consumption or intestinal mucosal surface area. Thus the use of short-term feeding with a saturated fatty acid diet in the prevention of acute irradiation damage to the intestine warrants further investigation in humans.
...
PMID:Saturated fatty acid diet prevents radiation-associated decline in intestinal uptake. 291 46

A model of nonischemic hypoxia of the jejunum was designed in dogs, by shunting of blood from the inferior vena cava directly into the regional mesenteric arterial supply, thereby lowering the PaO2 of the blood that reached the jejunal wall from 98.6 +/- 3 to 62 +/- 5 mm Hg. Absorption rates of sodium, glucose, fructose, glycine, and the dibasic aminoacid lysine were studied by in situ luminal perfusion of a 30-cm proximal jejunal segment with a bicarbonate buffer solution containing phenol red as a nonabsorbable marker for determination of water fluxes. During periods of control, hypoxia, and after discontinuation of the venoarterial admixture (recovery), effluent perfusate was collected and mucosal biopsies were obtained for assay of lactase, maltase and sucrase activity, mucosal ATPase activity and ATP content, and for light- and electron microscopic examination. Mesenteric supply with hypoxic blood was associated with a significant inhibition of Na+,K+-ATPase activity (p less than 0.001) and a rise in mucosal ATP content (p less than 0.05). There was a significant reduction in the absorption rates of sodium (p less than 0.001), glucose, and glycine (p less than 0.01), but no change in the transport of fructose and of lysine. Brush border enzymes were unaltered. The histological appearance of the mucosa remained normal throughout the experiment, but on electron microscopy a distinct swelling of the enterocyte mitochondria was noted during the hypoxia period.(ABSTRACT TRUNCATED AT 250 WORDS)
...
PMID:Effects of nonischemic hypoxia on jejunal mucosal structure and function: study of an experimental model in dogs. 294 46

The s.c. administration of cortisol to hamsters (50 mg/kg body wt/day for 4 days) produces a significant increase in maltase sucrase, alkaline phosphatase and leucineaminopeptidase activity in intestinal mucosa. Lactase activity is unaffected by cortisol. Gamma-glutamyltranspeptidase activity increases slightly in females but remains unchanged in males. Cortisol causes increase in proline and glycine absorption without changing the absorption of lysine.
...
PMID:The effect of cortisol on stimulation of enzymatic activity and absorption of amino acids in the small intestine of adult hamsters. 615 Jul 87

The effect of a single oral dose of endosulfan (5 mg/kg body weight) on the uptake of certain nutrients and brush-border enzymes has been studied in rat intestine. The uptake of glucose and alanine was elevated but that of leucine was decreased in endosulfan-fed rats. There was no change in the uptake of phenylalanine and lysine in insecticide-fed rats. The activities of brush-border sucrase and alkaline phosphatase were considerably increased while the activity of Na+ K+ ATPase was reduced in endosulfan-exposed animals. The leucine aminopeptidase activity was unaffected in pesticide-treated rats. There was a significant decrease in cellular LDH and GOT activities with no change in GPT activity. Neither was there a considerable increase in the cellular glucose-6-phosphatase activity (P less than 0.01) in the pesticide-fed rats. These results suggest that endosulfan toxicity induces certain functional changes in the intestine.
...
PMID:Effect of a single oral dose of endosulfan on intestinal uptake of nutrients and on brush-border enzymes in rats. 618 May 24


1 2 3 4 Next >>

---