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)

Pig duodeno-jejunal mucosa was maintained in organ culture for up to 24 h in Eagle's minimum essential medium containing 10% foal serum. Viability was controlled by determination of alkaline phosphatase and sucrase activity in the tissue. [14C]Leucine incorporation into proteins decreased 3-fold between 2 and 24 h. Newly synthesized secreted proteins were analyzed by SDS-polyacrylamide gel electrophoresis of the whole culture medium. Apolipoprotein A-I specifically measured by immunoelectrophoresis represented 10-20% of newly secreted proteins. Only 10% of apolipoprotein A-I secreted was recovered with the lipoprotein fraction (d less than 1.21). Recombination of the medium with porcine lipoproteins or DMPC vesicles prior to ultracentrifugation allowed, respectively, the recovery of 40 and 80% of apolipoprotein A-I secreted. The lipoprotein fractions also contained some apolipoproteins B and C and, after DMPC recombination, an apolipoprotein of Mr 45 000, most likely apolipoprotein A-IV, representing about 3.5% of newly secreted proteins. The d greater than 1.21 fractions all contained a high Mr protein, identified as IgA, and an unidentified protein of Mr approximately 45 000. The addition of colchicine (125 microM) to the culture medium did not significantly modify either tissue enzyme activities or [14C]leucine incorporation. It reduced total secretion by about 40% between 2 and 8 h of incubation, without interfering with apolipoprotein A-I secretion, which then represented up to 35% of secretion products. This raises the question of the mode of secretion of apolipoprotein A-I, which may be related to the high proportion of its which is secreted free.
...
PMID:Synthesis and secretion of apolipoproteins by pig intestinal mucosa in organ culture. Lack of inhibition of apolipoprotein A-I secretion by colchicine. 641 11

Little is known concerning the effects of elemental diets on bowel adaptation following massive resection. Fourteen of 28 Sprague-Dawley rats (40-45 g) were subjected to a 60% jejunoileal resection. Seven of the resected animals and seven sham-operated controls were then placed on a diet containing all protein in the form of casein hydrolysate. The remaining seven resected animals and seven sham-operated controls were placed on a comparable diet in which all the protein was casein. Each control animal was paired with a resected animal. After 2 weeks, unidirectional glucose and leucine transport was determined from intestinal sacs made from the proximal 3 cm and distal 3 cm of the remaining bowel. The midportion was used for the determination of mucosal weight and protein and sucrase content. When expressed as a percent increase over control values per centimeter of bowel, only sucrase levels were significantly elevated in the distal bowel in casein hydrolysate-versus casein-fed animals. The mucosal protein level, mucosal weight, and glucose uptake did not differ from control values when expressed as a percent change. Leucine uptake was significantly decreased in casein hydrolysate-fed animals when compared to that in casein-fed animals in both the proximal and distal bowel, again when expressed as a percent change from the control values. The administration of protein in the form of casein hydrolysate following massive bowel resection does not adversely affect mucosal hyperplasia occurring after resection but may have an adverse effect on the enhancement of amino acid absorption.
...
PMID:Effect of casein versus casein hydrolysate on mucosal adaptation following massive bowel resection in infant rats. 642 98

Patients undergoing massive small bowel resection for a variety of conditions develop severe nutrient malabsorption which gradually improves through mucosal hyperplasia in the remaining small intestine. Following massive small bowel resection, patients are generally fed elemental diets, often containing high concentrations of medium-chain triglycerides. We evaluated the effect of high percentage medium-chain triglyceride feeding on mucosal adaptation following massive small bowel resection in rats. Twenty 150-g Sprague-Dawley rats were subjected to 60% jejunoileal resection. Another 20 animals received sham operations. One-half of each group were fed a diet containing 83% of the fat as medium-chain triglycerides, the remainder were fed a diet containing 40% medium-chain triglycerides. Animals were pair-fed for 2 wk and subsequently killed. The remaining bowel was removed and unidirectional glucose and leucine uptake were measured using isolated sacs. Mucosal wet weight, protein, and sucrase content were determined. Animals fed medium-chain triglycerides demonstrated decreased mucosal weight in the proximal bowel, decreased mucosal sucrase activity in the proximal bowel, and decreased mucosal leucine uptake in the distal bowel. While medium-chain triglycerides offer an advantage to patients with short bowel syndrome because they are easily absorbed, they may not stimulate the same degree of mucosal adaptation following resection as long-chain triglyceride feedings.
...
PMID:Effect of high percentage medium-chain triglyceride diet on mucosal adaptation following massive bowel resection in rats. 644 Oct 12

The effect of dietary thiamin deficiency has been studied on intestinal functions and chemical composition of brush border membranes in rats. Intestinal uptake of glucose, glycine, alanine, and leucine was significantly stimulated in thiamin deficiency compared to pair-fed control group. Studies with glucose and glycine revealed that stimulation of the absorption process occurs only in the presence of Na+ but not in its absence. Km measured in the presence of 140 mM Na+ for glucose and glycine uptakes was reduced by 56 and 41%, respectively, but Vmax remained unaltered in vitamin deficiency. There was no change in these parameters in Na+-free medium (Km = 31.3 and 23.3 mM; Vmax = 17.2 to 19.7 and 13.5 to 16.4 mumol/10 min/g wet tissue, respectively) under these conditions. The activities of brush border sucrase, lactase, maltase, alkaline phosphatase, and leucine aminopeptidase were reduced by 42 to 66% in thiamin deficiency, compared to pair-fed controls. Kinetic studies with sucrase and alkaline phosphatase evinced that a decrease in Vmax (61 and 64%, respectively) with no change in Km (33.8 and 4.3 mM, respectively) was responsible for observed impairment in the enzyme activities in thiamin deficiency. Microvillus membrane proteins expressed on dry membrane basis were reduced by 20% in thiamin-deficient intestine. There was no difference in membrane sialic acid, cholesterol, phospholipids, and triglycerides fractions under these conditions. It is suggested that thinning of the microvillus membrane may be implicated in observed aberrations of intestinal functions in thiamin-deprived animals.
...
PMID:Effect of dietary thiamin deficiency on intestinal functions in rats. 646 54

When Saccharomyces carlsbergensis G-517 was grown in 10 mM galactose as the carbon source, the addition of 2-deoxy-D-glucose restricted the uptake of galactose, [3H]uridine and [3H]leucine, and restricted invertase synthesis (beta-D-fructofuranoside fructohydrolase; EC 3.2.1.26) for a period of 60-90 min. During this time, the radioactive antimetabolite was taken up by the cells; afterwards, invertase synthesis was enhanced, and the utilizaton rate of galactose, [3H]uridine and [3H]leucine increased until it reached that of the control culture. When glucose was used as a carbon source, sugar utilization and uptake of radioactive precursors were unaffected by addition of the deoxysugar.
...
PMID:Effects of 2-deoxy-D-glucose on the synthesis of RNA and protein in Saccharomyces carlsbergensis G-517. 677 89

Administration of a single oral dose of dieldrin (20 mg/kg body wt.) to rhesus monkeys considerably elevated the uptake of glucose and the activities of brush border sucrase, lactase, maltase and alkaline phosphatase in intestine compared to control animals. Leucine uptake and leucine amino peptidase activity was significantly depressed in pesticide-treated animals. Kinetic studies with brush border sucrase revealed that augmentation of enzyme activity in pesticide-fed animals was due to an increase in the disaccharidase content.
...
PMID:Acute dieldrin toxicity: effect on the uptake of glucose and leucine and on brush border enzymes in monkey intestine. 679 50

Amylase, alpha- and beta-glucosidase, alpha- and beta-galactosidase, beta-fructosidase, trypsin, aminotripeptidase, leucine-aminopeptidase, prolinase, prolidase glycyl-L-leucine dipeptidase and glygylglycine dipeptidase are present in the 3rd instar larvae of Chilo auricilius.
...
PMID:Digestive enzymes in the gut and salivary gland of the larvae of Chilo auricilius Ddgn. 698 21

Imposition of undernutrition during the suckling period considerably enhanced the intestinal uptake of D-glucose and glycine compared to a control group. Brush border sucrase, and alkaline phosphatase activities were drastically reduced while lactase and leucine amino peptidase levels were significantly elevated at weaning in nutritionally deprived pups as compared to control animals. Cortisone administration to undernourished rats depressed the uptake of D-glucose but stimulated that of glycine. Thyroxine treatment to undernourished animals reduced the uptake of glucose but had no effect on glycine absorption. Brush border sucrase and alkaline phosphatase activities were stimulated in cortisone- or thyroxine-injected undernourished rats but lactase activity was depressed under these conditions. Leucine aminopeptidase activity remained unaffected in cortisone- or thyroxine-administered undernourished pups.
...
PMID:Alterations in intestinal function in response to thyroxine and cortisone administration in undernourished rats. 713 57

Past investigation has revealed that the circadian rhythm of intestinal sucrase activity in rats is primarily cued by the time of feeding. We examined the mechanism of the circadian rhythm by methods involving quantitative immunoprecipitation of sucrase-isomaltase protein and study of decay of radioactively labeled protein. Rats were placed on a controlled feeding regimen (1000-1500 h) and then sacrificed at 3-h intervals over a 24-h period. Immunotitration experiments indicated that the circadian rhythm was the result of changes in the absolute amount of sucrase-isomaltase protein present and not of changes in the enzyme's catalytic efficiency. To study the mechanism of this circadian variation in sucrase-isomaltase mass, [(14)C]sodium carbonate was injected and, after maximum incorporation into brush border protein, the rats were sacrified at 3-h intervals. Sucrase-isomaltase protein was isolated by immunoprecipitation, and the decrease in total disintegrations per minute over time was used to study degradation of the protein. Enzyme degradation was not constant but exhibited a clear circadian rhythm. The period of increasing enzyme mass was characterized by virtual cessation of enzyme degradation (t((1/2)) of 38 h), and the period of declining enzyme mass by rapid degradation (t((1/2)) of 6 h or less). We found similar changes in enzyme degradation in fasted animals, demonstrating that the changes were not the result of decreased isotope reutilization during feeding. We found no evidence of a circadian rhythm in [(14)C]leucine incorporation into the protein, suggesting that enzyme synthesis was constant. These results indicate that the circadian rhythm of sucrase activity represents changes in the total amount of enzyme protein that are, at least in large part, secondary to changes in the enzyme's degradation rate.
...
PMID:Circadian rhythm of intestinal sucrase activity in rats. Mechanism of enzyme change. 736 44

We describe the changes of several brush-border enzymatic activities in different subpopulations of epithelial cells, separated sequentially from the villus tip-to-crypt axis of the small intestine, induced by deprivation of dietary nucleotides for different periods of time in adult rats. Deprivation of dietary nucleotides lead to a decrease in the content and specific activity of alkaline phosphatase, leucine-aminopeptidase, maltase, sucrase and lactase in the villus tip, but had little effect on the crypt zone. The effect of the nucleotide deprivation on the enzymatic activity progressively increased towards the tip of the villus. Since these enzymes are maturation markers of the intestinal cells, these results support the idea that dietary nucleotides affect the maturation status of small-intestine epithelium.
...
PMID:Maturation status of small intestine epithelium in rats deprived of dietary nucleotides. 772 91


<< Previous 1 2 3 4 5 6 7 Next >>

---