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)

The denaturation of eight purified yeast enzymes, glucose-6-phosphate dehydrogenase, 6-phosphogluconate dehydrogenase, glyceraldehyde-3-phosphate dehydrogenase, 3-phosphoglycerate kinase, alcohol dehydrogenase, beta-fructosidase, hexokinase and glucose-6-phosphate isomerase, promoted under controlled conditions by the free fatty acids myristic and oleic, is selective. Glucose-6-phosphate dehydrogenase (D-glucose-6-phosphate:NADP+ 1 oxidoreductase, EC 1.1.1.49) is extremely sensitive to destabilization and was studied in greater detail. Results show that chain length and degree of unsaturation of fatty acids are important to their destabilizing effect, and that ligands of the enzyme can afford protection. The denaturation process results in more than one altered form. These results can be viewed in the perspective of the possibility that amphipathic substances, and in particular free fatty acids, may play a role for enzyme degradation in vivo, by initiating steps of selective denaturation.
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PMID:Selective denaturation of several yeast enzymes by free fatty acids. 35 87

Two therapeutic regimens were compared in 16 infants with protracted diarrhea and malnutrition. Eight patients were treated with total parenteral nutrition given via a central vein (group A); the remaining eight patients received a combination of dilute parenteral nutrients given in a peripheral vein plus continuous enteral feedings of an elemental diet (group B). All patients recovered although two infants in group B were switched to TPN treatment after a poor response to the elemental diet. Intestinal biopsies were performed: (1) before treatment; (2) after 2 to 3 weeks of TPN or elemental diet; and (3) after 2 to 3 weeks of Nutramigen feedings. Before treatment, all patients had atrophic changes in the jejunal epithelium and deficient disaccharidase and trypsin activities. The second biopsy showed morphologic recovery in all patients, incomplete recovery of lactase and trypsin in both treatment groups, and complete recovery of sucrase and maltase activities only in group B patients. The third biopsy showed normal morphology and complete recovery of all enzymes measured. The mean number of hospital days was 46 +/- 4.8 for group A and 34 +/- 1.6 for group B (p less than 0.05) suggesting that patients given enteral feedings early tended to have a more rapid return of intestinal function and of some intestinal enzymes.
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PMID:Protracted diarrhea and malnutrition in infancy: Changes in intestinal morphology and disaccharidase activities during treatment with total intravenous nutrition or oral elemental diets. 81 May 53

This study was performed to determine whether the addition of alanyl-glutamine (Ala-Gln) can prevent intestinal mucosal atrophy induced by standard solution of total parenteral nutrition (S-TPN). Forty-one male Sprague-Dawley rats weighing 250 g were randomly divided into four groups: group I was killed after overnight fasting; group II received S-TPN. The other groups received S-TPN supplemented with amino acids other than glutamine (group III) or supplemented with Ala-Gln 2 g/100 mL (group IV); both solutions were isocaloric and isonitrogenous. After 1 week of TPN the rats were killed, and the duodenum, proximal jejunum, mid-small bowel, and distal ileum were obtained for morphologic and functional analysis. Weight gain did not differ significantly among these four groups, and there was no difference in nitrogen balance between groups III and IV. Serum glutamine in group IV (102.8 +/- 13.3 mumol/dL) was significantly increased (p less than .05) compared with groups I, II, and III (66.2 +/- 3.9, 55.7 +/- 7.8, and 61.3 +/- 10.8 mumol/dL, respectively). Mucosal wet weight, protein, RNA, sucrase, and maltase of group IV were significantly increased (p less than .05) compared with groups II and III. Villus height was significantly increased (p less than .05) in the jejunum of group IV rats compared with groups II and III, but not in any other segments of the intestine. No significant changes were observed in crypt depth among all groups. Diamine oxidase in groups II, III, and IV was significantly decreased (p less than .05) compared with group I in all segments except for the ileum.(ABSTRACT TRUNCATED AT 250 WORDS)
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PMID:The dipeptide alanyl-glutamine prevents intestinal mucosal atrophy in parenterally fed rats. 137 46

Urogastrone (UG) exerts trophic effects on the intestine and may play a role in maintaining normal intestinal structure and function. Since administration of nutrients parenterally results in intestinal hypoplasia and hypofunction, the aim of this study was to determine the effects of UG on intestinal structure and function in parenterally fed rats. Central venous catheters were placed into 28 Sprague-Dawley rats. Group I (n = 10) received TPN alone. Group II (n = 8) received TPN and 15 micrograms/day of UG and group III (n = 10) received rat chow ad libitum. The animals that received urogastrone had significantly greater (p less than 0.05) intestinal weight (25.6 +/- 2.5 mg/cm vs 22.6 +/- 3.0 mg/cm), mucosal weight (8.4 +/- 1.4 mg/cm vs 6.2 +/- 0.9 mg/cm), mucosal protein content (6.2 +/- 1.7 mg/cm vs 2.7 +/- 0.6 mg/cm), villous height (427 +/- 27 microns vs 293 +/- 75 microns), crypt cell production rate (14.5 +/- 1.4 metaphases/hr vs 12.3 +/- 0.7 metaphases/hr) and sucrase specific activity (6.5 +/- 2.6 vs 3.7 +/- 2.0) than animals receiving only TPN. However, these parameters remained less than in chow-fed animals. Thus, simultaneous infusion of UG prevents, in part, intestinal hypofunction and hypoplasia which occurs during TPN. This may be due to maintenance of mucosal proliferative activity and brush border enzyme activity.
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PMID:Urogastrone reduces gut atrophy during parenteral alimentation. 211 44

A rapid, enzyme-linked colorimetric assay, for the sequential determination of nanomole quantities of glucose and fructose in the same sample, has been developed for the measurement of fructosyl transferase activity in plant extracts. The assay extends the conventional dehydrogenase-linked assay for these sugars by utilizing the intermediary electron carrier, phenazine methosulfate, to couple NADP reduction to the production of a formazan dye from the tetrazolium salt, thiazolyl blue, in a form suitable for measurement using a microtiter plate reader. When the microtiter plate assay was used to measure the activities of yeast invertase and sucrose:sucrose fructosyl transferase from Lolium temulentum, results obtained were very similar to results obtained using the conventional procedure. The rapidity, small scale, and ease of execution of the method offers considerable advantages over the conventional hexose assay and is particularly suitable for screening of large numbers of small samples, exploiting both the speed of the microtiter plate reader and the facility of for microcomputer processing of data. The potential of this method for use with other enzyme systems and other metabolites is discussed.
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PMID:Colorimetric microtiter plate assay of glucose and fructose by enzyme-linked formazan production: applicability to the measurement of fructosyl transferase activity in higher plants. 344 22

Glycosidases and glycosyltransferases were electrophoresed in the presence of sodium dodecyl sulfate (SDS) in a thin-layer gel supported by a glass plate, treated with the nonionic detergent Triton X-100, and specifically stained for the sugar-releasing activity of these enzymes. Staining is based on conversion of monosugars or a sugar phosphate to glucose-6-phosphate by the appropriate intermediary enzymes, reduction of NADP+ to NADPH, and accumulation of reduced Nitroblue Tetrazolium in the gel. Among the enzymes tested, alpha-glucosidase, beta-glucosidase and beta-mannosidase could not be renatured, whereas beta-fructofuranosidase and alpha-mannosidase could be renatured unless heated before electrophoresis. Sucrose phosphorylase, glucosyltransferase and fructosyltransferase, which are single-peptide proteins with no cystine bond, could be renatured even after pretreatment with SDS and/or mercaptoethanol at 100 degrees C for 10 min. However, exclusive heating remarkably decreased the activities of these enzymes. Two-dimensional separation of the five renaturable enzymes was done in a single thin-layer gel, using SDS-electrophoresis in the first dimension and isoelectric focusing in the second dimension.
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PMID:Renaturation and activity staining of glycosidases and glycosyltransferases in gels after sodium dodecyl sulfate-electrophoresis. 752 70

Glucocorticoids promote the development of many organs including intestine. At the cellular level, the activity of glucocorticoids is regulated by 11 beta-hydroxysteroid dehydrogenase (11 beta HSD) which converts active glucocorticoids to inactive metabolites. As 11 beta HSD is also expressed in the intestine, this enzyme may be an important regulator of intestinal maturation. To investigate this, we have performed the systematic study of the development of intestinal 11 beta HSD activity and its cofactor preference as well as of the effect of 11 beta HSD inhibition by carbenoxolone on postnatal development of sucrase, alkaline phosphatase and Na,K-ATPase in the intestine. The activity of 11 beta HSD was low in ileum of suckling rats and significantly increased during the weaning period. In colon, the activity was already high in suckling rats and gradually rose during the postnatal development. 11 beta HSD activity was undetectable in jejunum both in young and adult rats. At 14.5 nM corticosterone, colonic 11 beta HSD utilized predominantly NAD as a cofactor, but displayed significant sensitivity also to NADP. Ileal 11 beta HSD had similar sensitivity to both cofactors. With NAD as a cofactor, ileal 11 beta HSD had a Km (59 +/- 10 nM) compatible with the colonic enzyme (81 +/- 14 nM). Carbenoxolone administration to suckling and weanling rats in vivo did not result in any changes of sucrase activity in jejunum and ileum, alkaline phosphatase activity in ileum and distal colon or Na,K-ATPase activity in ileum. However, carbenoxolone significantly increased Na,K-ATPase activity in distal colon. Our results indicate that the high-affinity type of 11 beta HSD is expressed not only in colon but also in ileum and that 11 beta HSD is an important factor in the regulation of tissue levels of active glucocorticoids in developing colon but not in the small intestine.
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PMID:The role of 11 beta-hydroxysteroid dehydrogenase in maturation of the intestine. 937 10

The enzymatic conversion of sugars to hydrogen could be a promising method for alternative fuel production. Maple tree sap is a source of environmental sugar (e.g., sucrose) that has the potential to be converted into hydrogen using the enzymes invertase, glucose dehydrogenase (GDH), hydrogenase, and glucose isomerase (GI) and the cofactor NADP+/NADPH. The kinetics of hydrogen production have been studied, and optimal conditions for hydrogen production are described. At low initial sucrose concentrations, in the absence of glucose isomerase, stoichiometric yields of 1 mol of H2/mol of sucrose were achieved. At higher sucrose concentrations, the yield of hydrogen declined so that at an initial sucrose concentration of 292 mM only 7% yield of hydrogen was obtained. The reason for this low yield was studied and shown not to be caused by enzyme inactivation or a pH drop during the reaction but due to an instability of the cofactor NADP+. Although gluconic acid inhibited both NADPH production and oxidation by GDH and hydrogenase, respectively, it was not the major cause of NADP+ instability. Fructose was also shown to be converted to hydrogen if GI was present in the reaction mixture. Also, by starting with sucrose, 1. 34 mol of H2/mol of sucrose was obtained if GI was present in the reaction mixture.
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PMID:Enzymatic conversion of sucrose to hydrogen 984 53

The compartmentation of key processes in sugar, organic acid and amino acid metabolism was studied during the development of the flesh and seeds of grape (Vitis vinifera L.) berries. Antibodies specific for enzymes involved in sugar (cell wall and vacuolar invertases, pyrophosphate: fructose 6-phosphate phosphotransferase, aldolase, NADP-glyceraldehyde-P dehydrogenase, cytosolic fructose 1,6-bisphosphatase), photosynthesis (Rubisco, fructose 1,6-bisphosphatase, sedoheptulose 1,7-bisphosphatase), amino acid metabolism (cytosolic and mitochondrial aspartate aminotransferases, alanine aminotransferase, glutamate dehydrogenase, glutamine synthetase), organic acid metabolism (phosphoenolpyruvate carboxylase, NAD- and NADP-dependent malic enzyme, ascorbate peroxidase), and lipid metabolism (acetyl CoA carboxylase, isocitrate lyase) were used to determine how their abundance changed during development. There were marked changes in the abundance of many of these enzymes in both the flesh and seeds. The intercellular location of some enzymes was investigated using immunohistochemistry. Several enzymes (e.g. phosphoenolpyruvate carboxylase and those involved in amino acid metabolism) were associated with tissues likely to function in the transport of imported assimilates, such as the vasculature. Although other enzymes (e.g. NADP-malic enzyme and soluble acid invertase, involved in the metabolism of sugars and organic acids) were largely present in the parenchyma cells of the flesh, their distribution was extremely heterogeneous. This study shows that when considering the metabolism of complex structures such as fruit, it is essential to consider how metabolism is compartmentalized between and within different tissues, even when they are apparently structurally homogeneous.
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PMID:An immunohistochemical study of the compartmentation of metabolism during the development of grape (Vitis vinifera L.) berries. 1093 59

In the apple variety 'Usterapfel', there are two known genotypes, which differ in malic acid content. One hundred days after full bloom, low-acid fruit (LA-fruit) contained 125 micromolg(-1) dry matter (DW) of malate, while the high-acid genotype (HA-fruit) reached levels up to 627 micromolg(-1) DW. There was no difference in the catalytic activity of enzymes involved in malate metabolism, such as PEPcarboxylase, malate dehydrogenase, and NADP malic enzyme. After [14C]glucose incorporation into the excised tissue of either genotype, the organic acid fraction was labeled to approximately the same extent. Furthermore, uptake of [14C]malate was significantly lower in excised tissue of LA-fruit. These findings suggest that low malate content in LA-fruit is the result of a restricted ability to accumulate malate in apple parenchyma cells. The different ability to accumulate malate had a pronounced effect on overall carbon partitioning. However, the rate of respiration and the rate of malate synthesis was similar in both genotypes. In HA-fruit, the glycolytic flux through pyruvate kinase was increased to compensate for the carbon that accumulated in the vacuole as malate. Since malate storage in the LA-fruit was restricted, it was more easily available for gluconeogenesis, and was correlated with a three-times higher activity of PEPcarboxykinase. LA-fruit showed higher concentrations of ATP, which stimulated Glc6P and fructose-6-phosphate formation. The elevated hexosephosphate content led to an enhanced partitioning of carbon into starch (+40%), hemicellulose (+104%), and sucrose (+40%) in more mature fruit. The activation of carbohydrate synthesis resulted in a significant drop in glucose-1-phosphate (Glc1P). To meet the increased demand for Glc1P, the activities of neutral and acid invertase, hexokinase, and phosphoglucomutase were higher in LA-fruit. Glucose was a more versatile substrate for this metabolic route than was fructose. It was also evident that glycolytic flux in apple was dependent on glucose level, and that the reaction catalysed by phosphoglucomutase contributed to the regulation of carbon partitioning between malate and carbohydrate polymers.
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PMID:Carbohydrate metabolism in two apple genotypes that differ in malate accumulation. 1549 4


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