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

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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)

An intracellular invertase was induced in cultures of Clostridium pasteurianum utilizing sucrose as its carbon source for growth. This enzyme synthesis could be repressed by the addition of fructose of a sucrose-growing culture. In contrast, invertase activity was not affected by the addition of glucose to sucrose-growing cells and this enzyme could be induced in a glucose-metabolizing culture by the addition of sucrose. This enzyme was purified 10.5-fold over the induced lese, EC 3.2.1.26) by substrate-specificity studies. Invertase had a pH optimum of 6.5 and an apparent Km of 79.5 mM for sucrose, and required high concentration of potassium phosphate for maximum activity. Invertase was completely inactivated by a 2-min heat treatment at 60 degrees C. This enzyme was strongly inhibited by p-hydroxymercuribenzoate (pCMB) and weakly inhibited by 5,5'-dithiobis(2-nitrobenzoic acid), while cysteine could substantially reverse pCMB) inhibition, suggesting that sulfhydryl group(s) were necessary for invertase activity.
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PMID:Regulation and properties of an invertase from Clostridium pasteurianum. 0 Jan 40

Preplant applications of potassium azide (KN3) to pine nursery beds were evaluated for effect on the soil microflora and on soil enzyme activity where either plastic-sealing or water-sealing techniques were used. Two weeks after incorporation of azide (0-224 kg/hs), soil samplings revealed reduced populations of bacteria and fungi and a corresponding decline in invertase and amylase activities. These effects were proportionate to the amount of azide used and were more pronounced in plastic-sealed plots. Phosphatase activity was little affected. Five weeks after azide application, bacterial populations were higher in treated plots than in controls. Greater numbers of bacteria were recorded from plastic-sealed plots and highest populations coincided with plots receiving the highest rates of azide, regardless of the sealing technique. Fungal populations at this sampling were generally less in treated plots than in the controls, but were higher under plastic seal. At this time, changes in invertase and amylase activities did not correspond to increased microbial numbers. Sixteen weeks after applications of KN3, bacterial populations in treated plots did not differ significantly from controls, but remained higher in plastic-sealed than water-sealed plots. Fungal populations under plastic seal had changed little and remained significantly lower in treated water-sealed plots than in controls. The earlier recorded reduction in invertase and amylase activities was still evident at the final sampling;
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PMID:Effects of potassium azide on soil microbial populations and soil enzymatic activities. 16 68

1. Stimulation of fluid secretion from fly salivary glands by 5-hydroxytryptamine (5-HT) is known to involve calcium and cyclic AMP. Isolated salivary glands were used to investigate the role of these second messengers in the control of enzyme (sucrase) secretion.2. The protein component of secretion from isolated glands treated with 5-HT appears to be identical to that of saliva secreted by flies during feeding.3. Stimulation of fluid secretion by 5-HT follows a definite dose-response curve, but there is no consistent relationship between the rate of enzyme secretion and the stimulating concentration of 5-HT.4. Exogenous cyclic AMP causes secretion of enzymes as well as of fluid, thus mimicking the action of 5-HT. The phosphodiesterase inhibitor theophylline enhances the rate of 5-HT-stimulated enzyme secretion.5. Removal of calcium from the bathing medium enhances enzyme secretion in response to 5 or 10 nM-5-HT but has no effect on enzyme secretion stimulated by 100 nM-5-HT or by cyclic AMP.6. Addition of 0.1 mM-lanthanum to medium containing 2 mM-calcium mimics the effect of calcium-free solution on 5-HT-stimulated enzyme secretion.7. The ionophore A 23187 causes secretion of both fluid and enzyme. The secretory rate is initially high but soon declines and ceases after about 40 min.8. Enzyme secretion in response to 5-HT or to cyclic AMP is progressively inhibited as the concentration of potassium is increased from 10 to 80 mM. Secretion in response to A 23187 is initially inhibited by 80 mM-potassium but then partially recovers.9. The rate of enzyme secretion appears to be affected by the intracellular concentrations of both calcium and cyclic AMP. It is possible that the rate of enzyme secretion increases as the intracellular calcium concentration rises, until the optimal calcium concentration is reached when further increase in the level of calcium progressively inhibits secretion. The optimal calcium concentration for enzyme secretion is lower than that for fluid secretion, and 5-HT normally causes maximal fluid secretion and submaximal enzyme secretion.
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PMID:The control of enzyme secretion from fly salivary glands. 20 76

Bakers' yeast (Saccharomyces cerevisiae) was equilibrated with distilled water and then packed into standardized pellets by centrifugation. The fractional space (S value) that was accessible to passive permeation was probed with a variety of mono- and divalent salts, mono- and disaccharides, polyols, substrates and products of beta-fructofuranosidase (EC 3.2.1.26) and acid phosphatase (EC 3.1.3.2), and a cross-linked polymer of sucrose (Ficoll 400). A simple but very reproducible method was developed to measure pellet volume. At the limit of zero osmolality for bathing medium, the interstitial space was 0.223 ml/ml of pellet, and the aqueous volume of cell envelopes was 0.117 ml/ml of pellet. Thus the cell envelope for this yeast, under these conditions, was approximately 15% of the total cell volume. At a finite osmolality, the space in a yeast pellet that was accessible to salt was accounted for by the sum of initial interstitial space, the volume of the cell envelopes, and the volume of water abstracted from the cells by osmosis. Plots of S value versus osmolality were linear for uncharged probes and curvilinear for all salts. When Ficoll and potassium thiocyanate were presented to the yeast in admixture, the S values for the salt increased continuously over the range of osmolality studied. However, the S values for Ficoll 400 (which did not penetrate the cell wall) were lower by an amount equilivalent to the cell envelopes; they increased in parallel with the S curve for salt up to 1.15 osmol/kg and then plateaued. The results support the concept of incipient plasmolysis at 1.15 osmol/kg, and the separation of protoplasm from the cell wall is indicated with more concentrated solutions. Such cells were still viable if slowly diluted in distilled water, but they were injured by the shock of rapid dilution. However, shocking the cells did not release beta-fructofuranosidase into the medium. The complete accessibility of salts toward killed cells was demonstrated with yeast that had been pretreated with heat, organic solvents, or glutaraldehyde.
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PMID:Permeability of the cell envelope and osmotic behavior in Saccharomyces cerevisiae. 40 15

A modified Roux-en-y repositioning of rat proximal small intestine resulted in a gut segment (A) exposed only to digestive secretions, but not to food and a gut segment (B) exposed to food, stomach juice and by reflux only to digestive secretions, and a third segment (C) exposed to both, food and digestive secretions. The changes in segment A were qualitatively very similar to those occurring after removal of luminal nutrition (intravenous feeding, self-emptying blind loop, and Thiry Vella loop). These findings support the hypothesis that the presence of luminal nutrition is a major factor regulating mucosal mass and enzyme activity in rat proximal small intestine. The changes in the luminal environment in segment B caused an increase in mucosal mass (in the proximal half only), an increase in sucrase activity which paralleled the increase in mucosal mass, and no change in activity of alkaline phosphatase which in fact was a decrease in activity ;at the cellular level'. Later on the net absorption of sodium and potassium was improved and the disappearance of galactose was unchanged when referred to unit length of small intestine.In segment C there was a small increase in mucosal mass, an increase in activity only for alkaline phosphatase, and an improvement of the net absorption of sodium without changes in the disappearance of galactose. These changes were compatible with a more proximal promotion of a distal gut segment.
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PMID:Analysis of the effects of food and of digestive secretions on the small intestine of the rat: III. Mucosal mass, activity of brush border enzymes, and in vivo absorption of galactose, sodium, and potassium. 68 Jun 2

Endogeneous hyperglucagonemia is observed in experimental diabetes mellitus and semistarvation, conditions associated with an increased intestinal absorptive function. To examine whether glucagon might exert a similar adaptive response on intestinal digestive-absorptive function like experimental diabetes mellitus the effect of chronic glucagon administration on intestinal transport of 3-0-methyl-D-glucose, water, sodium, potassium, and D-glucose induced transmural potential difference (PD) was examined by an in vivo perfusion technique in rat small intestine. Chronic administration of glucagon (100 mug twice daily) for 5 days resulted in increased absorption of 3-0-methyl-D-glucose, water, sodium and potassium as well as in an increase of D-glucose induced PD. A similar, but more pronounced augmentation of D-glucose induced PD was observed in the jejunum of streptozotocin-diabetic rats. Disaccharidase (maltase, sucrase, trehalase, lactase) and alkaline phosphatase activities were not affected in intestinal mucosa of glucagon-treated rats compared to controls. It cannot be decided from these results whether hyperglucagonemia is responsible for the adaptive intestinal changes observed in experimental diabetes mellitus.
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PMID:Effect of chronic glucagon-administration on the digestive and absorptive function of rat small intestine in vivo. 98 1

Gastric and intestinal phenotypic expression in 37 surgically obtained primary signet ring cell carcinomas, five of their metastases to lymph nodes, and three signet ring cell carcinomas transplanted into nude mice were determined by biochemical, mucin, histochemical, and ultrastructural studies. Crude extracts of cancer tissues were used for measurements of pepsinogen isozymes, sucrase, aminopeptidase (microsomal), and alkaline phosphatase. Histochemical staining of mucin by paradoxical concanavalin A, the galactose oxidase-Schiff sequence and sialidase-galactose oxidase-Schiff, and the periodate-borohydride technique/potassium hydroxide/periodic acid-Schiff procedure was performed. The procedures allowed clear definition of pyloric gland, surface mucous, small and large intestinal goblet, and intestinal absorptive cell types. Of 40 specimens examined, 19 consisted entirely of gastric-type cells, and three entirely of intestinal-type cells. The others consisted of mixtures of gastric and intestinal-type cells. The observed high incidence of intestinal-type cells in signet ring cell carcinomas suggested that intestinal-type cells develop independently from intestinal metaplasia within signet ring cell carcinomas (diffuse-type gastric cancers), which probably originate from nonmetaplastic gastric mucosa.
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PMID:Gastric and intestinal phenotypic expressions of human signet ring cell carcinomas revealed by their biochemistry, mucin histochemistry, and ultrastructure. 301

To investigate the effect of chronic protein-calorie malnutrition on intestinal repair after an enteric infection, we examined small intestinal structure, enzyme activity, and sodium transport in undernourished piglets during the acute and convalescent phases of a viral enteritis, transmissible gastroenteritis (TGE). Gnotobiotic pigs, nutritionally deprived from the age of 7 days, gained less weight than dietary controls from 14 days of age until the end of the study. Animals from malnourished and control diet groups were inoculated with TGE virus at 22-23 days and studied during the acute (40 h) and convalescent (4, 10, and 15 days) stages of this experimental enteritis along with noninfected dietary controls. After TGE infection, we observed a further decrease in weight gain and an increased mortality only in undernourished pigs. In jejunum and ileum of both dietary groups at 40 h after TGE infection, we observed comparable structural lesions, similar decreased activities of mucosal enzymes (sucrase, lactase, sodium-potassium-dependent ATPase), and increased thymidine kinase activities. Also we noted comparable diminution of glucose-stimulated jejunal sodium absorption in both dietary groups at 40 h. In control diet pigs, transport abnormalities recovered by 4 days after TGE infection and normal mucosal structure and enzyme activity returned over 4-15 days. In undernourished piglets, structural repair and enzyme abnormalities were prolonged when compared with the control diet group; glucose-stimulated sodium transport did not recover until 10 days after infection and never regained the enhanced activity seen in noninfected undernourished controls.(ABSTRACT TRUNCATED AT 250 WORDS)
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PMID:Impact of chronic protein-calorie malnutrition on small intestinal repair after acute viral enteritis: a study in gnotobiotic piglets. 392 24

1. A study was made of the composition and structure of walls isolated from yeast grown in continuous culture at different rates, under three conditions of glucose limitation in which the concentrations of glucose and ammonium sulphate in the medium and the oxygen-transfer rate in the culture were varied, and one condition of NH(4) (+) limitation. 2. The contents of total glucan and total mannan in the walls were relatively little affected by the growth rate under any of the four sets of conditions. The phosphorus and protein contents of walls from yeast grown under each of the four conditions increased as the growth rate was decreased. Walls from yeast grown under NH(4) (+) limitation contained only half as much protein as walls from cells grown under glucose limitation. The proportion of lipid was greatest in walls from yeast grown under NH(4) (+) limitation. 3. A procedure was devised for fractionating isolated walls, based on the ease with which the glucan and mannan were extracted with water and with hot and cold 6% (w/v) potassium hydroxide solution. The percentage of glucan, mannan, protein and phosphorus in each of the fractions was affected by the rate of growth and by the nature of the substrate limitation. 4. The beta-fructofuranosidase activities of yeast grown under glucose limitation increased as the growth rate was lowered, but decreased at very low growth rates. The effects at low growth rates were probably due to repression of enzyme synthesis by residual glucose in the culture filtrate. The beta-fructofuranosidase activities of yeast grown under NH(4) (+) limitation were much lower than those from yeast grown under any of the conditions of glucose limitation. 5. Yeast cells grown at any of the rates under NH(4) (+) limitation were longer and thinner than those grown at the same rate under any of the conditions of glucose limitation. Mean cell volumes were dependent on growth rate but not on the nature of the substrate limitation. 6. Electron micrographs of thin sections of isolated walls showed that cells grown under NH(4) (+) limitation had a more porous structure than those from cells grown under any of the conditions of glucose limitation.
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PMID:Effect of growth rate and substrate limitation on the composition and structure of the cell wall of Saccharomyces cerevisiae. 605 21

The pathogenesis of diarrhea caused by rotavirus infection was studied in miniature swine piglets. The animals were inoculated orally with 2 X 10(7) plaque-forming units of porcine rotavirus (OSU strain). During the height of diarrhea, intestinal function was investigated by in vivo perfusion of a 30-cm segment of proximal jejunum and a 30-cm segment of distal ileum. Absorption of Na+ and water decreased and 3-O-methylglucose transport was markedly reduced, P less than 0.01 compared to control animals. Mucosal lactase and sucrase levels were depressed in both the jejunum and ileum, P less than 0.001. Na+,K+-ATPase activity was significantly depressed only in the ileum, P less than 0.001. These changes were associated with a marked reduction in villous height, suggesting that the diarrhea could be an osmotic diarrhea due to nutrient (carbohydrate) malabsorption. Fresh stool samples were obtained and analyzed immediately for NA+,K+, osmolarity, glucose, and lactose; the osmotic gap was also determined. Stool osmolarity continually increased from 248 +/- 20 mosm/liter prior to inoculation to 348 +/- 20 mosm/liter at 75 +/- 1 hr postinoculation (P less than 0.005); the majority of the fecal osmotic gap could be accounted for by the amount of lactose present in the stools. Stool sodium increased from 34 +/- 6 mM prior to inoculation to a maximum of 65 +/- 4 mM at 53 +/- 1 hr postinoculation, P less than 0.001. There was no significant change in potassium concentration.(ABSTRACT TRUNCATED AT 250 WORDS)
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PMID:Pathogenesis of rotavirus-induced diarrhea. Preliminary studies in miniature swine piglet. 648 82


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