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)

Fusarium oxysporum produced maximum extracellular inulinase after 9 days of its growth at 25 degrees C on a medium (pH 5.5) containing 3% fructan and 0.2% sodium nitrate. The level of this enzyme decreased on the addition of either glucose, fructose, galactose or sucrose to F. oxysporum already growing on a fructan-containing medium. A significant increase in invertase production which resulted in an increase of the invertase/inulinase (S/I) ratio, was observed on addition of inulin to this fungus growing on other carbon sources. Glycerol (10%) gave better protection to inulinase against thermal denaturation at 50 degrees C compared to ethylene glycol and sorbitol. Inulinase immobilised in polyacrylamide gel retained 45% of its original activity. The immobilised enzyme showed a higher optimum temperature (45 degrees C) compared to free enzyme (37 degrees C). The immobilised enzyme after storage at 25 degrees C for 96 h showed 58% activity. Thermal stability of entrapped inulinase increased in the presence of inulin.
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PMID:Production, thermal stability and immobilisation of inulinase from Fusarium oxysporum. 136 87

The beta-fructosidases from the thermotolerant fungus, A. ficuum, were characterized. All were active as to inulin and sucrose hydrolysis with different specificity constants (kcat/Km). The enzymes were classified according to the ratio (alpha) of the specificity constants for inulin (I) and sucrose (S). The invertase showed an alpha value of lower than one, while the inulinases had alpha values of higher than one. The alpha ratio is proposed for the classification of beta-fructosidases into the inulinase (EC 3.2.1.7) and invertase (EC 3.2.1.26) groups. The amino acid composition, pH and temperature profiles, ultracentrifugation analysis results and effects of metal ions and effectors were studied. The data confirmed the preceding classification based on the I/S ratio, on the mode of action of inulinases (exo or endo) during inulin hydrolysis and on the molecular properties of the proteins.
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PMID:Molecular and kinetic properties of Aspergillus ficuum inulinases. 136 26

Bacillus subtilis 430A, isolated from the Vernonia herbacea (Vell Rusby) rhizosphere, produced an exocellular inulinase that fits the requirements for the production of syrups on an industrial scale. The partially purified enzyme, obtained by acetone precipitation, displayed a higher specificity for inulin (Km, 8 mM) than for sucrose (56 mM) and a total invertase/total inulase ratio of 0.62. In addition, it is stable at an optimal temperature of 45 to 50 degrees C for at least 7 h and is inhibited by the end product, fructose, at 14 mM.
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PMID:Characteristics of an inulinase produced by Bacillus subtilis 430A, a strain isolated from the rhizosphere of Vernonia herbacea (Vell Rusby). 176 8

Cell wall inulinase (EC 3.2.1.7) was purified from Kluyveromyces marxianus var. marxianus (formerly K. fragilis) and its N-terminal 33-amino acid sequence was established. PCR amplification of cDNA with 2 sets of degenerate primers yielded a genomic probe which was then used to screen a genomic library established in the YEp351 yeast shuttle vector. One of the selected recombinant plasmids allowed an invertase-negative Saccharomyces cerevisiae mutant to grow on inulin. It was shown to contain an inulinase gene (INU 1) encoding a 555-amino acid precursor protein with a typical N-terminal signal peptide. The sequence of inulinase displays a high similarity (67%) to S. cerevisiae invertase, suggesting a common evolutionary origin for yeast beta-fructosidases with different substrate preferences.
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PMID:Cloning and sequencing of the inulinase gene of Kluyveromyces marxianus var. marxianus ATCC 12424. 184 May 29

In synchronized continuous cultures of Saccharomyces cerevisiae CBS 8066, the production of the extracellular invertase (EC 3.2.1.26) showed a cyclic behavior that coincided with the budding cycle. The invertase activity increased during bud development and ceased at bud maturation and cell scission. The cyclic changes in invertase production resulted in cyclic changes in amounts of invertase localized in the cell wall. However, the amount of enzyme invertase present in the culture liquid remained constant throughout the budding cycle. Also, in asynchronous continuous cultures of S. cerevisiae, the production and localization of invertase showed significant fluctuation. The overall invertase production in an asynchronous culture was two to three times higher than in synchronous cultures. This could be due to more-severe invertase-repressive conditions in a synchronous chemostat culture. Both the intracellular glucose-6-phosphate concentration and residual glucose concentration were significantly higher in synchronous chemostat cultures than in asynchronous chemostat cultures. In the asynchronous and synchronous continuous cultures of S. cerevisiae, about 40% of the invertase was released into the culture liquid; it has generally been believed that S. cerevisiae releases only about 5% of its invertase. In contrast to invertase production and localization in the chemostat cultures of S. cerevisiae, no significant changes in inulinase (EC 3.2.1.7) production and localization were observed in chemostat cultures of Kluyveromyces maxianus CBS 6556. In cultures of K. marxianus about 50% of the inulinase was present in the culture liquid.
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PMID:Production and localization of beta-fructosidase in asynchronous and synchronous chemostat cultures of yeasts. 201 91

In the yeast Kluyveromyces marxianus two forms of inulinase were present, namely, an inulinase secreted into the culture fluid and an inulinase retained in the cell wall. Both forms were purified and analyzed by denaturing and nondenaturing polyacrylamide gel electrophoresis. With the use of endo-beta-N-acetyl-glucosaminidase H, it was established that the enzyme retained in the cell wall and the enzyme secreted into the culture fluid have similar subunits consisting of a 64-kDa polypeptide with varying amounts of carbohydrate (26 to 37% of the molecular mass). The two forms of inulinase differed in size because of their differences in subunit aggregation. The enzyme present in the culture fluid was a dimer, and the enzyme retained in the cell wall was a tetramer. The differences in oligomerization did not affect the apparent Km values towards the substrates sucrose and raffinose. These findings support the hypothesis that the retention of glycoproteins in the yeast cell wall may be caused by a permeability barrier towards larger glycoproteins. The amino-terminal end of inulinase was determined and compared with the amino terminus of the closely related invertase. The kinetic and structural evidence indicates that in yeasts two distinct beta-fructosidases exist, namely, invertase and inulinase.
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PMID:Structure and properties of the extracellular inulinase of Kluyveromyces marxianus CBS 6556. 213 69

In vivo hydrolysis of inulin and sucrose was examined in selected yeasts of the genus Kluyveromyces. Cells, grown in sucrose-limited chemostat cultures, were subjected to treatments for the removal of inulinase, the enzyme responsible for the hydrolysis of both inulin and sucrose. The effects of these treatments were studied by measurement of inulin-dependent and sucrose-dependent oxygen consumption by cell suspensions. In Kluyveromyces marxianus var. marxianus, inulinase was partially secreted into the culture fluid. Removal of culture fluid inulinase by washing had no effect on sucrose-dependent oxygen consumption by this yeast. However, this treatment drastically reduced inulin-dependent oxygen consumption. Treatment of washed cells with sulfhydryls removed part of the cell wall-retained inulinase and reduced inulin-dependent oxygen consumption by another 80%. Sucrose-dependent oxygen consumption was less affected, decreasing by 40%. Cell suspensions of K. marxianus var. drosophilarum, K. marxianus var. vanudenii, and Saccharomyces kluyveri rapidly utilized sucrose but not inulin. This is in accordance with the classification of these yeasts as inulin negative. Supernatants of cultures grown at pH 5.5 did not catalyze the hydrolysis of inulin and sucrose. This suggested that these yeasts contained a strictly cell-bound invertase, an enzyme not capable of inulin hydrolysis. However, upon washing, cells became able to utilize inulin. The inulin-dependent oxygen consumption further increased after treatment of the cells with sulfhydryls. These treatments did not affect the sucrose-dependent oxygen consumption of the cells. Apparently, these treatments removed a permeability barrier for inulin that does not exist for sucrose.(ABSTRACT TRUNCATED AT 250 WORDS)
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PMID:Localization of inulinase and invertase in Kluyveromyces species. 226 50

The yeast Kluyveromyces fragilis (ATCC 12424) was grown on a 2% inulin-1% yeast extract medium for 36 h and subsequently fixed with 0.5% glutaraldehyde. The glutaraldehyde treatment did not affect the beta-fructofuranosidase (inulinase, EC 3.2.1.7) activity of the cells but it did make the cells resistant to chemical and physical treatments that normally release beta-fructofuranosidase from untreated cells. The enzyme in the treated cells exhibited Km values for sucrose and raffinose identical to those obtained for the free enzyme. The cell wall of the treated cells exhibited the same diffusion properties for sucrose, raffinose, and inulin as those observed for untreated cells. The beta-fructofuranosidase was not bound covalently to the cell by the glutaraldehyde treatment. The results support the permeability barrier model for the enzyme retention in the yeast cell wall.
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PMID:The cell wall-associated inulinase of Kluyveromyces fragilis. 644 14

Debaryomyces phaffii possesses an inulinase activity which can be induced by growth on beta-fructosidase and particularly on inulin. The enzyme is located in the cell wall but is easily excreted into the culture medium. Maximum activity on inulin is observed at pH 4 and 50 degrees C. The Km on inulin is 1.2 X 10(-2) M. The enzyme breaks down inulin by splitting off terminal fructosyl units and it is active on sucrose and raffinose.
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PMID:Study of inulase from Debaryomyces phaffii Capriotti. 702 80

Debaryomyces cantarellii excretes into a buffered medium an inulinase of beta-fructofuranosidase type, its synthesis being induced by inulin. The enzyme has a pH optimum at 4 and its optimum temperature is 50 degrees C. Its Km for inulin is 15 mM.
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PMID:Inulinase of Debaryomyces cantarellii. 706 Oct 27


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