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)

Rates of glucose uptake in baker's yeast and in the osmophilic yeasts D. hansenii and S. rouxii were investigated at different values of water activity of the milieu, as regulated either by glycerol or sodium chloride. In both cases, D. hansenii could maintain relatively higher rates of glucose uptake. At lower values of water activity, sodium chloride exerted an inhibitory effect on rates of glucose uptake by S. rouxii, while in the presence of glycerol, rates of glucose uptake shown by S. rouxii resembled those shown by D. hansenii. Rates of glucose uptake by baker's yeast were drastically affected at lower values of water activity in the presence of either solute. Lower values of water activity exerted a stimulatory effect on catalase activity of both S. rouxii and D. hansenii. However, activities of baker's yeast with regard to catalase and invertase were moderately affected under such conditions. Results presented may lead to the presumption that osmophilic yeasts, at least partly, have solved the problem of osmotic tolerance over nonosmotolerant strains by possessing a high capacity for maintaining higher rates of glucose uptake, in spite of the adverse external concentration of solute.
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PMID:The effect of the water activity of the milieu on rates of glucose uptake by the osmophilic yeasts Saccharomyces rouxii and Debaryomyces hansenii. 74 15

Artificial multienzyme complexes were prepared in which enzymes were covalently bound to polysaccharide structures activated with urea and formaldehyde. Double enzyme complexes of glucose oxidase and catalase, a glucose oxidase and invertase, were prepared by immobilization on to cellulose fabric. Also, catalase was covalently bound to soluble dextran. The resulting multienzyme systems were highly active and stable, making them suitable for use in measuring the concentrations of glucose and saccharose in solutions. The measurements were performed using an amperometric oxygen electrode and multienzyme membranes containing glucose oxidase and catalase for the first substrate, as well as glucose oxidase bound to cheese-cloth and a 'liquid' membrane of dextran-bound catalase. To determine the concentration of saccharose, a multienzyme membrane with bound glucose oxidase and invertase was used in combination with a 'liquid' dextran-catalase. The enzyme electrodes exhibited a measuring range of 0.1-5 mol dm-3 and a response time of 2-3 min. The electrodes may be used for measuring saccharose and glucose concentrations both in fermentation broths and food products.
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PMID:Multienzyme membranes for biosensors. 137 9

Phytomonas sp. isolated from Euphorbia characias was adapted to SDM-79 medium. Cells isolated in the early stationary phase of growth were analyzed for their capacity to utilize plant carbohydrates for their energy requirements. The cellulose-degrading enzymes amylase, amylomaltase, invertase, carboxymethylcellulase, and the pectin-degrading enzymes polygalacturonase and oligo-D-galactosiduronate lyase were present in Phytomonas sp. and were all, except for amylomaltase, excreted into the external medium. Glucose, fructose and mannose served as the major energy substrates. Catabolism of carbohydrates occurred mainly via aerobic glycolysis according to the Embden-Meyerhof pathway, of which all the enzymes were detected. Likewise, the end-products of glycolysis, acetate and pyruvate, glycerol, succinate and ethanol were detected in the culture medium, as were the enzymes responsible for their production. Mitochondria were incapable of oxidizing succinate, 2-oxoglutarate, pyruvate, malate and proline, but had a high capacity to oxidize glycerol 3-phosphate. This oxidation was completely inhibited by salicylhydroxamic acid. No cytochromes could be detected either in intact mitochondria or in sub-mitochondrial particles. Mitochondrial respiration was not inhibited by antimycin, azide or cyanide. The glycolytic enzymes, from hexokinase to phosphoglycerate kinase, and the enzymes glycerol kinase, glycerol-3-phosphate dehydrogenase, phosphoenolpyruvate carboxykinase, malate dehydrogenase and adenylate kinase, were all associated with glycosomes that had a buoyant density of about 1.24 g cm-1 in sucrose. Cytochemical staining revealed the presence of catalase in these organelles. The cytosolic enzyme pyruvate kinase was activated by fructose 2,6-bisphosphate, typical of all other pyruvate kinases from Kinetoplastida. The energy metabolism of the plant parasite Phytomonas sp. isolated from E. characias resembled that of the bloodstream form of the mammalian parasite Trypanosoma brucei.
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PMID:Characterization of carbohydrate metabolism and demonstration of glycosomes in a Phytomonas sp. isolated from Euphorbia characias. 143 59

A Bacteroides fragilis strain isolated from human feces was the source of chromosomal DNA in the construction of plasmid pBS100. The cloned 6-kilobase insert of plasmid pBS100 conferred a sucrose positivity phenotype on transformed cells of Escherichia coli JA221. E. coli JA221(pBS100) cells were able to utilize sucrose as the sole source of carbon because of the presence of sucrase enzyme and sucrose uptake activities. Sucrase activity was inducible in B. fragilis but constitutive in E. coli JA221(pBS100) cells. In sucrose-minimal medium, both B. fragilis and E. coli JA221(pBS100) produced intracellular and extracellular sucrase activities throughout the growth cycle. Osmotic shock experiments performed on E. coli JA221(pBS100) indicated that up to 55% of the sucrase activity was localized in the periplasmic space, 30% was in the cytoplasm, and the remaining 15% was in the cell-free extracellular supernatant fluid. B. fragilis and E. coli JA221(pBS100) actively transported sucrose. Sucrose uptake was induced by sucrose in B. fragilis, whereas the uptake activity in E. coli JA221(pBS100) was constitutive. E. coli JA221(pBS100) appeared to transport sucrose by a phosphotransferase-independent system. B. fragilis transported sucrose only under strictly anaerobic conditions. No uptake activity was detected under aerobic conditions with or without addition of catalase.
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PMID:Expression and regulation of a Bacteroides fragilis sucrose utilization system cloned in Escherichia coli. 216 74

We report in detail the ontogeny and the response of antioxidant enzymes to glucocorticoids in the rat small intestine. Pregnant rats in the treatment group received four injections of dexamethasone starting on days 18, 19, or 20 of gestation; fetuses were killed 2 days later. Control rats were injected with 0.9% saline solution. Postnatal rats reaching 14, 19, and 104 days of age received four injections of hydrocortisone and were killed 2 days later. Age-matched controls were injected with 0.9% saline solution. The activities of xanthine oxidase, superoxide dismutase, and catalase were measured in small intestines from fetal (20 and 21 days gestation), newborn, and older (aged 16, 21, and 106 days) rats. Xanthine oxidase rose with maturation; the major increase occurred on postnatal day 21. Catalase and superoxide dismutase rose minimally during intrauterine life. On day 16 postpartum, catalase and superoxide dismutase values were 160% and 60%, respectively, higher than at birth. Glucocorticoid administration stimulated maltase and sucrase activities, but had no effect on the antioxidant enzymes or xanthine oxidase.
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PMID:Maturation of antioxidant enzymes in rat small intestine: lack of glucocorticoid stimulation. 362 18

The development of peroxisomes and expression of their enzymes were investigated in differentiating intestinal epithelial cells during their migration along the crypt-villus axis. Sequential cell populations harvested by a low-temperature method were identified by microscopy, determination of alkaline phosphatase and sucrase activities and incorporation of [3H]-thymidine into DNA. Ultrastructural cytochemistry after staining for catalase activity, revealed the presence of peroxisomes in undifferentiated stem cells located in the crypt region. Morphometry indicated that the number of these organelles increased as intestinal epithelial cells differentiate. Catalase activity was higher in the crypt cells than in the mature enterocytes harvested from villus tips. On the other hand, an increasing gradient of activity was observed from crypts to villus tips for peroxisomal oxidases, i.e. fatty acyl coA oxidase, D-amino acid oxidase and polyamine oxidase. These findings indicate that biogenesis of peroxisomes occurs during migration of intestinal epithelial cells along the crypt-villus axis and that peroxisomal oxidases contribute substantially to the biochemical maturation of enterocytes.
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PMID:Peroxisomes and peroxisomal enzymes along the crypt-villus axis of the rat intestine. 824 94

A study was made of the effect of the activity and purity of enzymes in the assay of total dietary fiber (AOAC Method 985.29) and specific dietary fiber components: resistant starch, fructan, and beta-glucan. In the measurement of total dietary fiber content of resistant starch samples, the concentration of alpha-amylase is critical; however, variations in the level of amyloglucosidase have little effect. Contamination of amyloglucosidase preparations with cellulase can result in significant underestimation of dietary fiber values for samples containing beta-glucan. Pure beta-glucan and cellulase purified from Aspergillus niger amyloglucosidase preparations were used to determine acceptable critical levels of contamination. Sucrose, which interferes with the measurement of inulin and fructooligosaccharides in plant materials and food products, must be removed by hydrolysis of the sucrose to glucose and fructose with a specific enzyme (sucrase) followed by borohydride reduction of the free sugars. Unlike invertase, sucrase has no action on low degree of polymerization (DP) fructooligosaccharides, such as kestose or kestotetraose. Fructan is hydrolyzed to fructose and glucose by the combined action of highly purified exo- and endo-inulinases, and these sugars are measured by the p-hydroxybenzoic acid hydrazide reducing sugar method. Specific measurement of beta-glucan in cereal flour and food extracts requires the use of highly purified endo-1,3:1,4 beta-glucanase and A. niger beta-glucosidase. Beta-glucosidase from almonds does not completely hydrolyze mixed linkage beta-glucooligosaccharides from barley or oat beta-glucan. Contamination of these enzymes with starch, maltosaccharide, or sucrose-hydrolyzing enzymes results in production of free glucose from a source other than beta-glucan, and thus an overestimation of beta-glucan content. The glucose oxidase and peroxidase used in the glucose determination reagent must be essentially devoid of catalase and alpha- and beta-glucosidase.
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PMID:Importance of enzyme purity and activity in the measurement of total dietary fiber and dietary fiber components. 1099 29

Salicylic acid treatment has been found to delay the ripening of banana fruits (Musa acuminata). Fruit softening, pulp:peel ratio, reducing sugar content, invertase and respiration rate have been found to decrease in salicylic acid treated fruits as compared with control ones. The activities of major cell wall degrading enzymes, viz. cellulase, polygalacturonase and xylanase were found to be decreased in presence of salicylic acid. The major enzymatic antioxidants namely, catalase and peroxidase, were also found to be decreased in presence of salicylic acid during banana fruit ripening.
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PMID:Delayed ripening of banana fruit by salicylic acid. 1099 48

Bioskin is a natural product produced by a mixed culture of Acetobacter xylinum, Saccharomyces cerevisiae and S. pombe cultured on media containing sucrose. It is of fibrillar nature able to retain some proteins, such as cytochrome c, by adsorption, and mainly composed of glucosamine and N-acetyl-D-glucosamine. This makes it possible that, at an adequate pH value, proteins charged as polyanionic molecules, such as catalase, can be retained by ionic adsorption using the positively charged amino groups of the matrix. In addition, bioskin can also be used as an affinity matrix to retain glycoproteins able to perform specific affinity reactions with the amino sugars of the matrix, such as invertase, fetuin or ovalbumin. Its possible use as a chromatographic support is discussed.
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PMID:Bioskin as an affinity matrix for the separation of glycoproteins. 1140 92

Glucokinase gene (HPGLK1) was cloned from a methylotrophic yeast Hansenula polymorpha by complementation of glucose-phosphorylation deficiency in a H. polymorpha double kinase-negative mutant A31-10 by a genomic library. An open reading frame of 1416 nt encoding a 471-amino-acid protein with calculated molecular weight 51.6 kDa was characterized in the genomic insert of the plasmid pH3. The protein sequence deduced from HPGLK1 exhibited 55 and 46% identity with glucokinases from Saccharomyces cerevisiae and Aspergillus niger, respectively. The enzyme phosphorylated glucose, mannose and 2-deoxyglucose, but not fructose. Transformation of HPGLK1 into A31-10 restored glucose repression of alcohol oxidase and catalase in the mutant. Transformation of HPGLK1 into S. cerevisiae triple kinase-negative mutant DFY632 showed that H. polymorpha glucokinase cannot transmit the glucose repression signal in S. CEREVSIAE: synthesis of invertase and maltase in respective transformants was insensitive to glucose repression similarly to S. cerevisiae DFY568 possessing only glucokinase.
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PMID:Cloning and characterization of glucokinase from a methylotrophic yeast Hansenula polymorpha: different effects on glucose repression in H. polymorpha and Saccharomyces cerevisiae. 1238 17


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