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)

A 52-kDa protein, CEL3, has been separated from the culture filtrate of Agaricus bisporus during growth on cellulose. A PCR-derived probe was made, with a degenerate oligodeoxynucleotide derived from the amino acid sequence of a CEL3 CNBr cleavage product and was used to select cel3 cDNA clones from an A. bisporus cDNA library. Two allelic cDNAs were isolated. They showed 98.8% identity of their nucleotide sequences. The deduced amino acid sequence and domain architecture of CEL3 showed a high degree of similarity to those of cellobiohydrolase II of Trichoderma reesei. Functional expression of cel3 cDNA in Saccharomyces cerevisiae was achieved by placing it under the control of a constitutive promoter and fusing it to the yeast invertase signal sequence. Recombinant CEL3 secreted by yeast showed enzymatic activity towards crystalline cellulose. At long reaction times, CEL3 was also able to degrade carboxymethyl cellulose. Northern (RNA) analysis showed that cel3 gene expression was induced by cellulose and repressed by glucose, fructose, 2-deoxyglucose, and lactose. Glycerol, mannitol, sorbitol, and maltose were neutral carbon sources. Nuclear run-on analysis showed that the rate of synthesis of cel3 mRNA in cellulose-grown cultures was 13 times higher than that in glucose-grown cultures. A low basal rate of cel3 mRNA synthesis was observed in the nuclei isolated from glucose-grown mycelia.
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PMID:The cel3 gene of Agaricus bisporus codes for a modular cellulase and is transcriptionally regulated by the carbon source. 808 21

The stability of invertase was studied under various conditions, including at 75 degrees C, in presence of stabilizers (sorbitol and glycerol) at 75 degrees C, and in the presence of denaturants (urea and trichloroacetic acid) at 37 degrees C in reverse micelles. Stability of the invertase in reverse micelles was found to be improved over that of the enzyme in bulk aqueous solution. Sorbitol could enhance enzyme stability as it does in the bulk aqueous system. The stabilizing effect of glycerol was reduced in reverse micelles. The denaturation pattern of urea remains unaltered. However, the denaturation effect of trichloroacetic acid has been reduced in reverse micelles.
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PMID:Stability of invertase in reverse micelles. 875 13

In the past, the fermentation activity of Saccharomyces cerevisiae in substrates with a high concentration of sucrose (HSuc), such as sweet bread doughs, has been linked inversely to invertase activity of yeast strains. The present work defines the limits of the relationship between invertase activity and fermentation in hyperosmotic HSuc medium. Fourteen polyploid, wild-type strains of S. cerevisiae with different invertase levels gave a similar ranking of fermentation activity in HSuc and in medium in which glucose and fructose replaced sucrose (HGF medium). Thus, invertase is unlikely to be the most important determinant of fermentation in sweet doughs. Yeasts produce the compatible solute-osmoprotective compound glycerol when exposed to hyperosmotic environments. Under low sugar concentrations (and nonstressing osmotic pressure), there was no correlation between glycerol and fermentation activities. However, there was a strong correlation between the ability of yeasts to ferment in HSuc or HGF medium and their capacity to produce and retain glycerol intracellularly. There was also a strong correlation between intracellular glycerol and fermentation activity of yeasts in a medium in which the nonfermentable sugar alcohol sorbitol replaced most of the sugars (HSor), but the ability to produce and retain glycerol was greater when yeasts were incubated in HGF medium under the same osmotic pressure. The difference between the amounts of glycerol produced and retained in HSor and in HGF media varied with strains. This implies that high fermentable sugar concentrations cause physiological conditions that allow for enhanced glycerol production and retention, the degree of which is strain dependent. In conclusion, one important prerequisite for yeast strains to ferment media with high concentrations of sugar is the ability to synthesize glycerol and especially to retain it.
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PMID:Influence of invertase activity and glycerol synthesis and retention on fermentation of media with a high sugar concentration by Saccharomyces cerevisiae. 897 48

By fusing the upstream activation sequence (UAS) of ADH2 gene to the 5' end of a series of deletions in the upstream region of SUC2 gene, 4 expression plasmids YFD110 delta 1, YFD110 delta 9, YFD110 delta 17 and YFD110 delta 11 were constructed. They contained different hybrid promoters for transcription of SUC2 gene. After transforming them together with two control plasmids YFD26 delta 1, YFD25 into yeast. S. cerevisiae Y33 respectively, the transformants were grown in the repression or derepression media and the invertase produced by each transformants were analyzed by colormetry and gel electrophoresis. The results were as follow is: (1) UASSUC2 and UASADH2 in the hybrid plasmid YFD110 delta 1 worked synergically under derepression condition. Under repression condition, Y33/YFD110 delta 1 produced very low level of glycosylation invertase. (2) Compared with three different derepression media, the medium containing low concentration glucose gave higher derepression efficiency of glycosylated invertase than the media containing glycerol and ethanol.
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PMID:[Construction of yeast ADH2-SUC2 hybrid promoter and its regulation in gene expression]. 957 60

The non-pathogenic, dimorphic, ascomycetous yeast Arxula adeninivorans LS3 is halotolerant. It can grow in a minimal medium containing up to 20% NaCl. The growth parameters are only weakly influenced by 10% NaCl. However, NaCl in a concentration higher than 10% causes a decrease in the specific growth rate, a longer adaptation phase and a lower cell count in the stationary growth phase. Concentrations of glycerol and trehalose, which differed 100-fold in magnitude in a salt free medium, are also influenced differently by salt. NaCl induces accumulation of intracellular glycerol in exponentially growing cells but a reduced concentration of intracellular trehalose in stationary cells. Transcripts of the genes ARFC3, encoding a component of the replication factor C, and GAA, encoding a secretory glucoamylase, can be detected only in cells cultured in media with NaCl concentrations below 10%. Furthermore, NaCl in high concentration reduces the level of secreted proteins including glucoamylase end invertase.
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PMID:Halotolerance of the yeast Arxula adeninivorans LS3. 1095 59

This report represents the conclusions of a Joint FAO/WHO Expert Committee convened to evaluate the safety of various food additives and contaminants, with a view to recommending Acceptable Daily Intakes (ADIs) and tolerable intakes, respectively, and to prepare specifications for the identity and purity of food additives. The first part of the report contains a general discussion of the principles governing the toxicological evaluation of food additives (including flavouring agents) and contaminants, assessments of intake, and the establishment and revision of specifications for food additives. A summary follows of the Committee's evaluations of toxicological and intake data on various specific food additives (diacetyltartaric and fatty acid esters of glycerol, quillaia extracts, invertase from Saccharomyces cerevisiae, beta-carotene from Blakeslea trispora, curcumin, phosphates, diphosphates and polyphosphates, hydrogenated poly-1-decene, natamycin, D-tagatose, carrageenan, processed Eucheuma seaweed, curdlan, acetylated oxidized starch, alpha-cyclodextrin and sodium sulfate), flavouring agents and contaminants (3-chloro-1,2-propanediol, 1,3-dichloro-2-propanol, and a large number of polychlorinated dibenzodioxins, polychlorinated dibenzofurans and coplanar polychlorinated biphenyls). Annexed to the report are tables summarizing the Committee's recommendations for ADIs of the food additives and tolerable intakes of the contaminants considered, changes in the status of specifications of these food additives and specific flavouring agents, and further information required or desired.
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PMID:Evaluation of certain food additives and contaminants. 1256 44

Aspergillus niger produces extracellular beta-fructofuranosidase under submerged (SmF) and solid state fermentation (SSF) conditions. After UV mutagenesis of conidiospores of A. niger, 2-deoxyglucose (10 g/l) resistant mutants were isolated on Czapek's minimal medium containing glycerol as a carbon source and the mutants were examined for improved production of beta-fructofuranosidase in SmF and SSF conditions. One of such mutant DGRA-1 overproduced beta-fructofuranosidase in both SmF and SSF conditions. In SmF, the mutant DGRA-1 showed higher beta-fructofuranosidase productivity (110.8 U/l/hr) than the wild type (48.3 U/l/hr). While in SSF the same strain produced 322 U/l/hr of beta-fructofuranosidase, 2 times higher than that of wild type (154.2 U/l/hr). In SmF, both wild type and mutants produced relatively low level of beta-fructofuranosidase in medium containing sucrose with glucose than from the sucrose medium. However in SSF, the DGRA-1 mutant grown in sucrose and sucrose+ glucose did not show any difference with respect to beta-fructofuranosidase production. These results indicate that the catabolite repression of beta-fructofuranosidase synthesis is observed in SmF whereas in SSF such regulation was not prominent.
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PMID:Beta-fructofuranosidase production by 2-deoxyglucose resistant mutants of aspergillus niger in submerged and solid-state fermentation. 1258 33

The PKC1 gene in the yeast Saccharomyces cerevisiae encodes protein kinase C that is known to control a mitogen-activated protein (MAP) kinase cascade consisting of Bck1, Mkk1 and Mkk2, and Mpk1. This cascade affects the cell wall integrity but the phenotype of Pkc1 mutants suggests additional targets which have not yet been identified. We show that a pkc1Delta mutant, as opposed to mutants in the MAP kinase cascade, displays two major defects in the control of carbon metabolism. It shows a delay in the initiation of fermentation upon addition of glucose and a defect in derepression of SUC2 gene after exhaustion of glucose from the medium. After addition of glucose the production of both ethanol and glycerol started very slowly. The V(max) of glucose transport dropped considerably and Northern blot analysis showed that induction of the HXT1, HXT2 and HXT4 genes was strongly reduced. Growth of the pkc1Delta mutant was absent on glycerol and poor on galactose and raffinose. Oxygen uptake was barely present. Derepression of invertase activity and SUC2 transcription upon transfer of cells from glucose to raffinose was deficient in the pkc1Delta mutant as opposed to the wild-type. Our results suggest an involvement of Pkc1p in the control of carbon metabolism which is not shared by the downstream MAP kinase cascade.
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PMID:Evidence for involvement of Saccharomyces cerevisiae protein kinase C in glucose induction of HXT genes and derepression of SUC2. 1270 97

Glucose and other sugars, such as galactose or maltose, are able to cause carbon catabolite repression in Saccharomyces cerevisiae. Although glycolytic intermediates have been suggested as signal for repression, no evidence for such a control mechanism is available. The establishment of a correlation between levels of intracellular metabolites and the extent of catabolite repression may facilitate the identification of potential signal molecules in the process. To set a framework for such a study, the repression produced by xylose, glycerol and dihydroxyacetone upon genes belonging to different repressible circuits was tested, using an engineered strain of S. cerevisiae able to metabolize xylose. Xylose decreased the derepression of various enzymes in the presence of ethanol by at least 10-fold; the corresponding mRNAs were not detected in these conditions. Xylose also impaired the derepression of galactokinase and invertase. Glycerol and dihydroxyacetone decreased 2- to 3-fold the derepression observed in ethanol or galactose but did not affect invertase derepression. For yeast cells grown in media with different carbon sources, no correlation was found between repression of fructose-1,6-bisphosphatase and intracellular levels of glucose 6-phosphate or fructose 1,6-bisphosphate.
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PMID:Xylose and some non-sugar carbon sources cause catabolite repression in Saccharomyces cerevisiae. 1295 10

Some strains of Candida utilis produce exceptionally large amounts of extracellular and total invertase. Strain Y-900 of C. utilis produces high yields whether the carbon source is sucrose, glucose, maltose, or xylose and still higher yields with lactic acid, glycerol, and ethyl alcohol. Approximately 20 to 30% of the total invertase of C. utilis is extracellular. Strains of Saccharomyces cerevisiae and Saccharomyces carlsbergensis are generally inferior to C. utilis in production of extracellular and total invertase, the difference being accentuated in shaken cultures. The industrial yeasts are generally superior in invertase production to the other yeasts included in the survey.
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PMID:Production of extracellular and total invertase by Candida utilis, Saccharomyces cerevisiae, and other yeasts. 1372 51


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