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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)

In three profiles of a semi-gley soil under the floodplain forest, variations were studied in the activities of invertase, amylase, cellobiase, cellulase, proteases, and phosphatases. In the surface soil layer, enzymatic activity was found affected by the soil moisture at a significant level, whereas in the deeper soil layers the influence of aeration was more effective. Moreover, significant correlations could be detected between the amount of available nitrogen and protease activity, while the water-soluble phosphorus acted as a represeive agent on the activity of phosphatases. Existence of correlations between the numbers of microbes and enzymes could be demonstrated for invertase and protases only.
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PMID:Enzymatic activity in a semi-gley soil under the floodplain forest in South Moravia. 20 42

The activities of pectin-methyl-esterase, polygalacturonase, cellulase, amylase, saccharase, and protease of strains of Fusarium oxysporum (Schlecht.) f.sp. pisi (Linford) were studied. The selected strains showed different symptoms and different degrees of pathogenicity on the host plant. The measurements were performed during the growth of strains at constant temperatures and, in another experiment, on the day at different temperatures at which the individual strains were grown. Activities were determined by the plate methods and by the spectrophotometric method. It has been found that enzyme activity of the strains with different degree of pathogenicity show considerable differences in dependence on temperature and growth dynamics.
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PMID:The effect of temperature and age of strains of Fusarium oxysporum on its enzymatic activity. 47 66

The stability and activity of three hydrolytic enzymes, acid phosphatase (EC 3.1.3.2), beta-fructofuranosidase (EC 3.2.1.26), and beta-glucosidase (EC 3.2.1.4), were studied at 30 degrees C in two-phase systems. They were prepared with equal quantities of buffered water and a water-immiscible organic solvent. Low-molecular-weight acetates and paraffins were tested in this investigation. The kinetic constant of storage inactivation was correlated with the logarithm of solvent polarity. Enzyme stability in the presence of organic phases, whose log P value was included in 1.2-2.2, was greater than the one measured in pure buffered aqueous media. On the other hand, a dramatic enzyme denaturation took place making use of solvents at higher log P-value. Experiments carried out during the 24-h operation clarified that the reaction yield does not depend solely on solvent polarity. Acid phosphatase and beta-glucosidase, which are less resistant than beta-fructofuranosidase to temperature and shear in buffered solutions, showed especially significant enhancement of catalytic activity when hydrolysis was performed with the addition of acetates (50% v/v).
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PMID:Hydrolytic reactions in two-phase systems. Effect of water-immiscible organic solvents on stability and activity of acid phosphatase, beta-glucosidase, and beta-fructofuranosidase. 136 38

The addition of Tween 80 and sucrose monopalmitate, nonionic surfactants, to fungal cultures resulted in marked increases in yields of the enzymes cellulase, amylase, sucrase, beta-1 --> 3 glucanase, xylanase, purine nucleosidase, and benzoyl esterase. The action appears to be an effect of the surfactant on cell permeability.
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PMID:Surfactants as stimulants of enzyme production by microorganisms. 581 98

We have studied changes in the activity of some lytic enzymes contained in mycelium of Aspergillus niger in cultures relative to the autolytic phase of growth. Acid phosphatase, polygalacturonidase and alpha-amylase activity reached its highest level (40.7, and 8 U/sample, respectively) at the initiation of the autolytic phase of growth. 1.3-beta-Glucanase and beta-N-acetylglucosaminidase reached its highest level (3.5 and 2 U/sample, respectively) during the first days of autolysis. Alkaline phosphatase, cellulase, invertase, esterase, chitinase and proteolytic activity is also present in autolysing mycelium of A. niger, though comparatively low. Their maximum activity coincided with the beginning of the autolytic phase of growth. In all enzymes studied here, as autolyis proceeded, enzyme activity decreased by about 90%. Only esterase activity remained nearly constant throughout the whole period of autolysis described here.
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PMID:Lytic enzyme activity in autolysing mycelium of Aspergillus niger. 634 2

Based on a glucose oxidase sensor for determination of glucose several glucoseoxidase bioenzyme electrodes have been developed. Enzymes producing glucose by hydrolysis of saccharides (glucamylase, invertase, cellulase) as well as glucose consuming systems (hexo-kinase, glucose dehydrogenase) have been coupled to glucose oxidase. The function of the bienzyme systems was demonstrated by concentration measurements (blood glucose, maltose, ATP, NAD+, starch) and enzyme activity measurements (alpha-amylase, ATPase, lactate dehydrogenase).
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PMID:Glucose oxidase bienzyme electrodes for ATP, NAD+, starch and disaccharides. 677 73

In the autolytic phase of growth Schizophyllum commune lost 62% of its dry weight in 70 days of incubation. The variations in the activity of some lytic enzymes were studied in the culture fluid and mycelial extracts during growth and autolysis of this fungus. The enzymes 1,3-beta-glucanase (exoglucanase), 1,3(4)-beta-glucanase (endoglucanase), alpha-amylase, and invertase behaved in the same way in culture fluid and mycelial extract, but their activities were much higher in the culture fluid. The enzyme activities increased during autolysis, but then decreased at the end of this period except in the case of alpha-amylase which remained high. It was only possible to detect 1,6-beta-glucanase, cellulase, and polygalacturonase activities at certain times during the autolytic phase of growth. The enzyme chitinase was not detected and 1,3-alpha-glucanase (S-glucanase) occurred in the mycelial extract at a higher concentration than in the culture fluid. A decrease in the activity of this enzyme in the mycelial extract and an increase in the culture fluid occurred during autolysis. The enzyme 1,3-alpha-glucanase exhibited two optima pH, one at 6.0 and the other at 8.0. The Km value for the latter was 0.02 M at pH 5.5 in borate-citrate-phosphate buffer.
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PMID:Lytic enzymes in the autolysis of Schizophyllum commune with special reference to 1,3-alpha-glucanase. 697 66

Activities of twelve hydrolytic enzymes in the digestive tract of young rabbits before weaning (4 weeks old) and adult rabbits (3 months old) were measured. The principal digestive enzymes in both groups of rabbits appeared to be amylase (EC 3.2.1.1), maltase (EC 3.2.1.20), pectinase (EC 3.2.1.15) and proteinases. The stomach of young rabbits contained most of the lipolytic activity and 45.7% of the total proteolytic activity of the digestive tract. The highest specific activities (per g digesta) of amylase, maltase and proteinase in young rabbits were found in the small intestine. Total activities (per segment) of amylase and maltase in the small intestine and the caecum were similar. Activities of cellulase (EC 3.2.1.4), inulinase (EC 3.2.1.7) and beta-glucosidase (EC 3.2.1.21) were low and activity of pectinase was fairly high in all segments of the digestive tract. The highest activity of urease (EC 3.5.1.5) was found in the caecum. Enzymic profiles of the colonic chymus resembled those of the caecum. Total hydrolytic activity was lower in the colon than in the caecum. Specific activities of amylase and invertase (EC 3.2.1.26) were lower and those of inulinase and lactase (EC 3.2.1.23) higher in 4-week-old rabbits than in 3-month-old rabbits. Gastric proteinase represented almost half of the total proteolytic activity of the digestive tract, whereas lipolytic activity of gastric contents was not found in measurable quantities in adult rabbits. The caecal contents of adult rabbits contained most of the total activity of lipase (EC 3.1.1.3), cellulase, xylanase (EC 3.2.1.32), pectinase, lactase, invertase, beta-glucosidase and urease present in the digestive tract.(ABSTRACT TRUNCATED AT 250 WORDS)
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PMID:Distribution of activity of hydrolytic enzymes in the digestive tract of rabbits. 753 89

Enzyme storage stability and hydrolysis yield were measured in experiments carried out with three model hydrolytic enzymes: acid phosphatase (EC 3.1.3.2), beta-glucosidase (EC 3.2.1.4), and beta-fructofuranosidase (EC 3.2.1.26) entrapped in hydrogels of poly(2-hydroxyethyl methacrylate). Runs were performed at 30 degrees C, under intensive stirring (500 rev min-1), in 50% v/v biphasic media prepared with buffer and organic solvents, whose log P value varied from 0.68 to 8.8. Storage stability was also monitored in the pure solvents. The small average particle size (125-210 microns) and the intensive stirring eliminate hindrances of intra- and interphase mass transfer resistances. The hydrophilic matrix protects the enzymes against thermal and chemical deactivation, thus allowing good production per unit weight of biocatalyst. In biphasic media, storage stability, with the exception of acid phosphatase, was not dependent on solvent polarity. On the contrary, a significant trend was observed when the enzymes were stored in neat organic solvents.
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PMID:Stability and activity of immobilized hydrolytic enzymes in two-liquid-phase systems: acid phosphatase, beta-glucosidase, and beta-fructofuranosidase entrapped in poly(2-hydroxyethyl methacrylate) matrices. 776 4

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


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