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

---

Query: EC:3.2.1.26 (invertase)
4,927 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

The initial step of disaccharide dissimilation by Actinomyces viscosus serotype 2 strain M-100 was studied. Sucrase activity was found in the 3,000 X g particulate fraction and the 37,000 X g soluble fraction of the cells, whereas lactase activity was found almost exclusively in the 37,000 X g soluble fraction. Neither sucrase nor lactase activity was appreciable in the culture liquor. Sucrose phosphorylase, alpha-glucosidase, and polysaccharide synthesis activities were not observed in the soluble cell fraction. The sucrase was identified as invertase (EC 3.2.1.26; beta-D-fructofuranoside fructohydrolase). The lactase was identified as beta-galactosidase (EC 3.2.1.23; beta-D-galactoside galactohydrolase). The enzymes in the 37,000 X g soluble fraction were separable by diethylamino-ethyl-cellulose chromatography, giving one beta-galactosidase peak and one major and one minor invertase peak. Acrylamide gel electrophoresis showed different electrophoretic mobilities of the enzymes. The molecular weight of the beta-galactosidase is about 4.2 X 10(5) and that of invertase is about 8.6 X 10(4). The beta-galactosidase has a Km for lactose of about 6 mM and a pH optimum between pH 6.0 and 6.5. The major invertase component has a Km for sucrose of about 71 mM and a pH optimum between pH 5.8 and 6.3.
...
PMID:Identification, separation, and preliminary characterization of invertase and beta-galactosidase in Actinomyces viscosus. 1 74

A recessive mutant cat1-1, wild type CAT1, was isolated in Saccharomyces cerevisiae. It did not grow on glycerol nor ferment maltose even with fully constitutive, glucose resistant maltase synthesis. It prevented derepression of isocitrate lyase, fructose-1,6-diphosphatase and maltase in a constitutive but glucose sensitive maltase mutant. Derepression of malate dehydrogenase was retarded and slowed down. Sucrose fermentation and invertase synthesis was not affected. Respiration was normal. From this mutant, two reverse mutants were isolated. One was recessive, acted as a suppressor of cat1-1 and was called cat2-1, wild type CAT2; the other was dominant and allelic to CAT1 and designated CAT1-2d and cat2-1 caused an earlier derepression of enzymes studied but did not affect the repressed nor the fully derepressed enzyme levels. CAT1-2d and cat2-1 did not show any additive effects. It is proposed that carbon catabolite repression acts in two ways. The direct way represses synthesis of sensitive enzymes, during growth on repressing carbon sources whereas the other way regulates the derepression process. After alleviation of carbon catabolite repression, gene CAT1 becomes active and prevents the activity of CAT2 which functions as a repressor of sensitive enzyme synthesis. The CAT2 gene product has to be eliminated before derepression can actually occur. The time required for this causes a delay in derepression after the depletion of a repressible carbon source. cat1-1 cannot block CAT2 activity and therefore, derepression is blocked. cat2-1 is inactive and derepression can start after carbon catabolite repression has ceased. CAT1-2d permanently active as a repressor of CAT2 and eliminates the delay in derepression.
...
PMID:Genetics of carbon catabolite repression in Saccharomycess cerevisiae: genes involved in the derepression process. 19 40

Sucrose catabolism was studied in Rhodopseudomonas capsulata. Sucrose was hydrolysed by the action of a constitutive cytoplasmic sucrase. The use of a glucose-6-phosphate dehydrogenase-deficient mutant and radiorespirometric experiments demonstrated that both the glucose and fructose moieties of sucrose were catabolized via the Entner-Doudoroff pathway. This result was confirmed by enzyme analysis and studies on sugar assimilation. All the enzymes of the Entner-Doudoroff pathway were present in bacteria grown on secrose but fructokinase (EC 1.7.1.4) activity was relatively low. In contrast, phosphoenolpyruvate:fructose phosphotransferase and 1-phosphofructokinase, the key enzymes for the catabolism of exogenous fructose, were only partially induced. Bacteria grown on sucrose and treated with chloramphenicol were, therefore, not able to assimilate exogenous fructose. We conclude that under these conditions endogenous fructose is catabolized via the Entner-Douboroff pathway, while exogenous fructose is degraded via fructose 1-phosphate and the Embden-Meyerhof pathway.
...
PMID:An alternative pathway for the degradation of endogenous fructose during the catabolism of sucrose in Rhodopseudomonas capsulata. 64 27

Pea leaves were illuminated in air containing 150 or 1000p.p.m. of 14CO2 for various times. Alternatively, segments of wheat leaves were supplied with [3-14C]serine for 40 min in the light in air with 145, 326 or 944p.p.m. of 12CO2. Sucrose was extracted from the leaf material, hydrolysed with invertase, and 14C in the pairs of carbon atoms C-3+C-4, C-2+C-5 and C-1+C-6 in the glucose moiety was measured. The results obtained after metabolism of 14CO2 were consistent with the operation of the photosynthetic carbon-reduction cycle; the effects of CO2 concentration on distribution of 14C in the carbon chain of glucose after metabolism of [3-14C]serine is more easily explained by metabolism through the glycollate pathway than by the carbon-reduction cycle.
...
PMID:Intramolecular labelling of sucrose made by leaves from [14C)carbon dioxide or [3-14C]serine. 65 73

Sucrase activity was studied in 13 strains of Streptococcus mutans representing the five Bratthall serotypes. Sucrose-adapted cells have sucrase activity in the 37,000 x g-soluble fraction of all strains. The enzyme was identified as invertase (beta-d-fructofuranoside fructohydrolase; EC 3.2.1.26) because it hydrolyzed the beta-fructofuranoside trisaccharide raffinose, giving fructose and melibiose as its products, and because it hydrolyzed the beta-fructofuranoside dissacharide sucrose, giving equimolar glucose and fructose as its products. Invertases of c and e strains exhibit two activity peaks by molecular exclusion chromatography with molecular weights of 45,000 to 50,000 and about 180,000; those of serotypes a, b, and d strains exhibit only a single component of 45,000 to 50,000 molecular weight. The electrophoretic mobility of invertases is different between the serotypes and the same within them. Inorganic orthophosphate (P(i)) has a weak positive effect on the V(max) of invertases of serotypes c and e cells but a strong positive effect on the invertases of serotype b cells; P(i) has a strong positive effect on the apparent K(m) of the invertases of serotype d cells, but has no effect on the V(max); P(i) has a strong positive effect on both the apparent K(m) and V(max) of the invertases of serotype a cells. Thus, the invertases were different between all of the serotypes but similar within the serotypes. These findings support the taxonomic schemes of Coykendall and of Bratthall. It was additionally noted that 37,000 x g-soluble fractions of only serotypes b and c but not serotypes a, d, and e cells have melibiase activity, and it could be deduced that serotype d cells lack an intact raffinose permease system.
...
PMID:Comparative study of invertases of Streptococcus mutans. 87 12

Saccharase-isomaltase deficiency was discovered in five children. The diagnosis was made on the basis of an abnormal oral saccharose loading response and demonstrating decreased activity of intestinal saccharase and isomaltase in the presence of normal small-intestinal mucosa. Three children failed to thrive, and all had recurrent diarrhoea. The diagnosis was made in children aged six to twenty-two months. Treatment consisted of saccharose-free diet or feeding with an enzyme preparation, Bi-Myconase. Saccharose-containing foods were increasingly tolerated beyond the second year of life so that children aged 2 1/2 to 3 1/4 years no longer required special treatment.
...
PMID:[Congenital saccharase-isomaltase deficiency: a six-year survey (author's transl)]. 126 33

The adjacent sacX and sacY genes are involved in sucrose induction of the Bacillus subtilis sacB gene by an antitermination mechanism. sacB, encoding the exoenzyme levansucrase, is also subject to regulation by the DegS-DegU signalling system. Using sacXY'-lacZ and sacX'-lacZ fusions, we show that the transcription of the sacX and sacY genes is both inducible by sucrose and regulated by DegU. sacX and sacY appear to constitute an operon, since the deletion of the sacX leader region abolished the expression of a sacXY'-lacZ fusion. The degU-dependent promoter was located by deletion analysis and reverse transcriptase mapping 300 nucleotides upstream from the sacX initiator codon. Sucrose induction of the sacX'-lacZ fusion requires either SacY or the homologous SacT antiterminator, which is involved in sucrose induction of the intracellular sucrase gene (sacPA operon). Sequence analysis of the sacX leader region revealed (20 nucleotides downstream from the transcription start site) a putative binding site for these regulators; however, no structure resembling a rho-independent terminator could be found overlapping this site, unlike the situation for sacPA and sacB. Deletion of a segment of the leader region located 100 nucleotides downstream from this site led to constitutive expression of the sacXY'-lacZ and sacX'-lacZ fusions. These results suggest that the mechanism of sucrose induction of sacXY is different from that of sacPA and sacB.
...
PMID:Transcription of the Bacillus subtilis sacX and sacY genes, encoding regulators of sucrose metabolism, is both inducible by sucrose and controlled by the DegS-DegU signalling system. 140 Jan 59

Sucrose transport from the apoplasm, across the plasma membrane, and into the symplast is critical for growth and development in most plant species. Phloem loading, the process of transporting sucrose against a concentration gradient into the phloem, is an essential first step in long-distance transport of sucrose and carbon partitioning. We report here that a soybean 62-kD sucrose binding protein is associated with the plasma membrane of several cell types engaged in sucrose transport, including the mesophyll cells of young sink leaves, the companion cells of mature phloem, and the cells of the developing cotyledons. Furthermore, the temporal expression of the gene and the accumulation pattern of the protein closely parallel the rate of sucrose uptake in the cotyledon. Molecular cloning and sequence analysis of a full-length cDNA for this 62-kD sucrose binding protein indicated that the protein is not an invertase, contains a 29-amino acid leader peptide that is absent from the mature protein, and is not an integral membrane protein. We conclude that the 62-kD sucrose binding protein is involved in sucrose transport, but is not performing this function independently.
...
PMID:A 62-kD sucrose binding protein is expressed and localized in tissues actively engaged in sucrose transport. 146 54

Sucrose-positive derivatives of Escherichia coli K-12, containing the plasmid pUR400, and of Klebsiella pneumoniae hydrolyse intracellular sucrose 6-phosphate by means of an invertase into D-glucose 6-phosphate and free D-fructose. The latter is phosphorylated by an ATP-dependent fructokinase (gene scrK of an scr regulon) to D-fructose 6-phosphate. The lack of ScrK does not cause any visible phenotype in wild-type strains of both organisms. Using genes and enzymes normally involved in D-arabinitol metabolism from E. coli C and K. pneumoniae, derivatives of E. coli K-12 were constructed which allowed the identification of scrK mutations on conventional indicator plates. Cloning and sequencing of scrK from sucrose plasmid pUR400 and from the chromosome of K. pneumoniae revealed an open reading frame of 924 bp in both cases--the equivalent of a peptide containing 307 amino acid residues (Mr 39 and 34 kDa, respectively, on sodium dodecyl sulphate gels). The sequences showed overall identity among each other (69% identical residues) and to a kinase from Vibrio alginolyticus (57%) also involved in sucrose metabolism, lower overall identity (39%) to a D-ribose-kinase from E. coli, and local similarity to prokaryotic, and eukaryotic phosphofructokinases at the putative ATP-binding sites.
...
PMID:Molecular analysis of two fructokinases involved in sucrose metabolism of enteric bacteria. 180 35

In higher plants sucrose plays a central roles with respect to both short-term storage and distribution of photoassimilates formed in the leaf. Sucrose is synthesized in the cytosol, transiently stored in the vacuole and exported via the apoplast. In order to elucidate the role of the different compartments with respect to sucrose metabolism, a yeast-derived invertase was directed into the cytosol and vacuole of transgenic tobacco plants. This was in addition to the targeting of yeast-derived invertase into the apoplast described previously. Vacuolar targeting was achieved by fusing an N-terminal portion (146 amino acids long) of the vacuolar protein patatin to the coding region of the mature invertase protein. Transgenic tobacco plants expressing the yeast-derived invertase in different subcellular compartments displayed dramatic phenotypic differences when compared to wild-type plants. All transgenic plants showed stunted growth accompanied by reduced root formation. Starch and soluble sugars accumulated in leaves indicating that the distribution of sucrose was impaired in all cases. Expression of cytosolic yeast invertase resulted in the accumulation of starch and soluble sugars in both very young (sink) and older (source) leaves. The leaves were curved, indicating a more rapid cell expansion or cell division at the upper side of the leaf. Light-green sectors with reduced photosynthetic activity were evenly distributed over the leaf surface. With the apoplastic and vacuolar invertase, the phenotypical changes induced only appear in older (source) leaves. The development of bleached and/or necrotic sectors was linked to the source state of a leaf. Bleaching followed the sink to source transition, starting at the rim of the leaf and moving to the base. The bleaching was paralleled by the inhibition of photosynthesis.
...
PMID:Transgenic tobacco plants expressing yeast-derived invertase in either the cytosol, vacuole or apoplast: a powerful tool for studying sucrose metabolism and sink/source interactions. 184 80


1 2 3 4 5 6 7 8 9 10 Next >>

---