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)

Debaromyces cantarellii Capriotti contains an inulinase activity which is inducible by growth on inulin but not on other beta-fructosides. The induction is inhibited by glucose and fructose. The system is situated in the cell wall and can be best extracted with a 20 mM phosphate buffer at pH 8.5. The inulinase activity shows pH optima at 4 and 6, suggesting the presence of two enzymes, the latter being more tightly bound to the cell wall. Both enzymes degrade inulin from the nonreducin end. The cells also contain a constitutive beta-fructofuranosidase with a specificity partly overlapping with that of the inulinase(s).
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PMID:Inulinase activity of Debaromyces cantarellii. 735 6

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

The enzyme levanase encoded by the sacC gene from Bacillus subtilis was overexpressed in Escherichia coli with the strong, inducible tac promoter. The enzyme was purified from crude E. coli cell lysates by salting out with ammonium sulfate and chromatography on DEAE-Sepharose CL-6B, S-Sepharose, and MonoQ-Sepharose. The purified protein had an apparent molecular mass of 75,000 Da in sodium dodecyl sulfate-polyacrylamide gel electrophoresis, which is in agreement with that expected from the nucleotide sequence. Levanase was active on levan, inulin, and sucrose with Km values of 1.2 microM, 6.8 mM, and 65 mM, respectively. The pH optimum of the enzyme acting on inulin was 5.5, and the temperature optimum was 55 degrees C. Levanase was rapidly inactivated at 60 degrees C, but activity could be retained for longer times by adding fructose or glycerol. The enzyme activity was completely inactivated by Ag+ and Hg2+ ions, indicating that a sulfhydryl group is involved. A ratio of sucrase to inulinase activity of 1.2 was found for the purified enzyme with substrate concentrations of 50 mg/ml. The mechanism of enzyme action was investigated. No liberation of fructo-oligomers from inulin and levan could be observed by thin-layer chromatography and size exclusion chromatography-low-angle laser light scattering-interferometric differential refractive index techniques. This indicates that levanase is an exoenzyme acting by the single-chain mode.
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PMID:Purification and characterization of the Bacillus subtilis levanase produced in Escherichia coli. 764 30

For expression of the alpha-galactosidase gene from Cyamopsis tetragonoloba in Kluyveromyces marxianus CBS 6556 we have used the promoter of the homologous inulinase-encoding gene (INU1). The INU1 gene has been cloned and sequenced and the coding region shows an identity of 59% with the Saccharomyces cerevisiae invertase gene (SUC2). In the 5'-flanking region of INU1 we found a sequence (TAAATCCGGGG) that perfectly matches to the MIG1 binding consensus sequence (WWWWTSYGGGG) of the S. cerevisiae GAL1, GAL4 and SUC2 genes. Using the K. marxianus INU1 promoter and prepro-signal sequence, we obtained a high alpha-galactosidase production level (153 mg/l) and a secretion efficiency of 99%. Both the production level and the secretion efficiency were significantly reduced when the INU1 pro-peptide was deleted. With either the S. cerevisiae PGK or GAL7 promoter we could obtain only low alpha-galactosidase production levels (2 mg/l).
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PMID:Expression of an alpha-galactosidase gene under control of the homologous inulinase promoter in Kluyveromyces marxianus. 776 85

The Bacteroides fragilis BF-1 fructanase-encoding gene (fruA) was cloned and expressed in Escherichia coli from the recombinant plasmid pBS100. The fruA gene consisted of 1,866 bp encoding a protein of 622 amino acids with a calculated M(r) of 70,286. The apparent M(r) of the fructanase, determined by in vitro cell-free transcription-translation and sodium dodecyl sulfate-polyacrylamide gel electrophoresis analysis, was approximately 71,500. An alignment of the amino acid sequences of the B. fragilis BF-1 fructanase and the Bacillus subtilis levanase revealed that 45.5% of the amino acids were identical. The fruA gene was expressed in E. coli from its own promoter; however, no E. coli promoter-like sequence was evident upstream from the gene. A major E. coli transcription start point and a single B. fragilis BF-1 transcription start point were located. Expression of the fruA gene was constitutive in E. coli(pBS100) and B. fragilis BF-1. The ratio of sucrase activity to inulinase activity (S/I ratio) was constant for enzyme preparations from E. coli (pBS100), indicating that both activities were associated with the fructanase. For B. fragilis BF-1, the S/I ratio varied considerably depending on the carbon source used for growth, suggesting that a separate sucrase is produced in addition to the fructanase in B. fragilis BF-1. Localization experiments and TnphoA mutagenesis indicated that the fructanase was exported to the periplasm. Sequence analysis of the N-terminal region of the fructanase revealed a putative 30-amino-acid signal peptide. The enzymatic properties of the purified fructanase were investigated. The enzyme was able to hydrolyze sucrose, raffinose, inulin, and levan but not melezitose, indicating that it was a beta-D-fructofuranosidase which was able to hydrolyze beta(2-->6)-linked fructans.
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PMID:Molecular characterization of a fructanase produced by Bacteroides fragilis BF-1. 849 24

A genomic library from the yeast Pichia anomala has been constructed and employed to clone the gene encoding the sucrose-hydrolysing enzyme invertase by complementation of a sucrose non-fermenting mutant of Saccharomyces cerevisiae. The cloned gene, INV1, was sequenced and found to encode a polypeptide of 550 amino acids which contained a 22 amino-acid signal sequence and ten potential glycosylation sites. The amino-acid sequence shows significant identity with other yeast invertases and also with Kluyveromyces marxianus inulinase, a yeast beta-fructofuranosidase which has a different substrate specificity. The nucleotide sequences of the 5' and 3' non-coding regions were found to contain several consensus motifs probably involved in the initiation and termination of gene transcription.
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PMID:Cloning and sequence analysis of the invertase gene INV 1 from the yeast Pichia anomala. 859 69

The Actinomyces naeslundii T14V gene levJ encodes a sucrase with fructanase activity and may be responsible for the fructanase activity observed bound to the surface of A. naeslundii T14V cells. A large proportion of LevJ expressed in Escherichia coli was translocated to the periplasm, and translocation and enzymatic activity were not affected by deletion of a putative cell-wall anchor sequence. The pH optimum of the enzyme was found to be between 5.5 and 6.5 whether the substrate was sucrose or inulin, although inulinase activity was more sensitive than sucrose activity to perturbation of the pH from the optimum. The relation between LevJ inulinase activity and pH was similar to that of A. naeslundii whole cells. LevJ exhibited standard saturation kinetics with sucrose, and the K(m) was calculated to be 89 mM, but it was not possible to calculate a K(m) for inulin. Evidence for inhibition of inulinase activity but not sucrase activity by high concentrations of inulin was obtained.
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PMID:Biochemical studies on LevJ, a fructanase from Actinomyces naeslundii T14V. 893 47

This is the first report describing the gene structure and the enzymatic properties of a beta-fructosidase of a hyperthermophilic organism. The bfrA gene of the ancestral bacterium Thermotoga maritima MSB8 codes for a 432-residue, polypeptide of about 50 kDa, with significant sequence similarity to other beta-fructosidases. On the basis of its primary structure, BfrA can be assigned to glycosyl hydrolase family 32. The bfrA gene was expressed in Escherichia coli and the recombinant enzyme was purified and characterised. BfrA was specific for the fructose moiety and the beta-anomeric configuration of the glycosidic linkages of its substrates. The enzyme released fructose from sucrose and raffinose, and the fructose polymer inulin was hydrolysed quantitatively in an exo-type fashion. BfrA displayed similar catalytic efficiencies for the hydrolysis of sucrose and inulin with Kcat/K(m) values (at 75 degrees C, pH 5.5) of about 4.1 x 10(4) M-1S-1 and 3.1 x 10(4) M-1S-1 respectively. BfrA had an optimum temperature of 90-95 degrees C (10-min assay) and was extremely insensitive to thermo-inactivation. During 5 h at temperatures up to 80 degrees C at pH 7, the enzyme retained at least 85% of its initial activity. Thus, BfrA is the most thermostable beta-fructosidase and also the most thermostable inulinase described to date. In conclusion, the T. maritima enzyme can be classified as an exo-beta-D-fructofuranosidase (EC 3.2.1.26) with invertase and inulinase activity. Its catalytic properties along with the extreme thermostability recommend it for use in biotechnology.
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PMID:Analysis of the gene for beta-fructosidase (invertase, inulinase) of the hyperthermophilic bacterium Thermotoga maritima, and characterisation of the enzyme expressed in Escherichia coli. 972 Feb 1

The stimulation of glucose phosphorylation in isolated hepatocytes by low fructose concentrations is transient due to the rapid metabolism of fructose. To prolong this stimulatory effect fructose was enzymically generated in the incubation medium from either sucrose with invertase or inulin with inulinase. A maximal rate of glucose phosphorylation was achieved when fructose was formed at at least 0.01 micromol/min, which maintained a concentration of 70 microM fructose in the medium. In the presence of a fructose concentration of 70 microM, the rate of phosphorylation with 5 mM glucose was doubled and remained constant over a 2.5 h period. Under these conditions the rate of glycolysis was increased more than 3-fold. The stimulation of flux through glucokinase by low concentrations of fructose decreased the proportion of glucose phosphorylated, which was cycled between glucose and glucose 6-phosphate, and increased the proportion that was glycolysed. The method described for maintaining the stimulation of glucose phosphorylation by isolated hepatocytes over prolonged incubation periods is especially suited to the further study of the control of glucokinase activity, in particular how the variation of flux through glucokinase affects the flux through all the pathways that utilize the product, glucose 6-phosphate.
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PMID:Long-term maintenance of low concentrations of fructose for the study of hepatic glucose phosphorylation. 989 93

Kluyveromyces lactis, a budding yeast related to Saccharomyces cerevisiae, can grow on a wider variety of substrates and shows less sensitivity to glucose repression than does Saccharomyces cerevisiae. Many genes that are subject to glucose repression in S. cerevisiae are repressed only weakly or not at all in K. lactis. The molecular basis for this difference is largely unknown. To compare the mechanisms that regulate glucose repression in K. lactis and S. cerevisiae, we decided to clone and analyse an invertase gene from K. lactis. The SUC2 gene, which encodes invertase in S. cerevisiae, is strongly regulated by glucose and serves as a model system for studies on glucose repression. The invertase gene of K. lactis, KlINV1, was isolated by colony hybridization using a conserved region within the inulinase gene of K. marxianus as a probe. Two independent clones obtained were shown to contain the same ORF of 1827 bp. The deduced amino acid sequence is 59% similar to that of the K. marxianus inulinase and shows 49% similarity to ScSuc2p. Gene disruption experiments and low-stringency Southern analysis indicate that KlINV1 is a unique gene in K. lactis. Northern analysis revealed that the transcription of KlINV1 is strongly repressed in the presence of glucose, but, in contrast to the case in S. cerevisiae, repression is independent of KlMig1p.
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PMID:Glucose repression of the Kluyveromyces lactis invertase gene KlINV1 does not require Mig1p. 1039 24


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