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)

In the large granule fraction of rat liver, the density distribution of inhibitor-sensitive neutral ribonuclease is similar to that for acid hydrolases and its density distribution is similarly modified by Triton WR-1339 accumulation in lysosomes. Particulate neutral ribonuclease is latent; the enzyme is unmasked by very low digitonin concentrations or hypoosmotic shock. These observations demonstrate that the bulk of liver neutral ribonuclease is associated with the lysosomal system. In view of the neutral pH optimum of the enzyme and of some particularities of its distribution in fractionation experiments, the possiblilty of an extrahepatic origin of neutral ribonuclease has been investigated. After partial pancreatectomy, a significant decrease is observed in both plasma and liver neutral ribonuclease. The effect is specific, for it does not occur for other lysosomal enzymes. Also, labelled bovine pancreatic ribonuclease, when injected intravenously, is taken up by the liver. The sedimentable labelled enzyme has a density distribution similar to the distribution of other foreign proteins, horseradish peroxidase or yeast invertase. These results are explained by the uptake of plasmatic neutral ribonuclease from pancreatic origin by the liver.
Eur J Biochem 1975 Dec 15
PMID:Hepatic nucleases. Extrahepatic origin and association of neutral liver ribonuclease with lysosomes. 0 Dec 73

Conduritol-B-epoxide, a compound structurally related to the substrates of external yeast beta-fructosidase (beta-D-fructofuranoside fructohydrolase, EC 3.2.1.26), is an active-site directed inhibitor of this enzyme. The inactivation is irreversible and first-order with respect to time and inhibitor concentration. From the kinetic data obtained, it is concluded that one molecule of inhibitor reacts with one molecule of the enzyme causing inactivation. The inactivation is prevented by the presence of substrates. The pH-dependence of inactivation shows two dissociating groups in the enzyme with pKa values 3.05 and 6.8 being involved in the inactivation process. A carboxylate at the active site with pKa 3.05 is suggested to be the reactive group with conduritol-B-epoxide.
Biochim Biophys Acta 1976 Dec 08
PMID:External yeast beta-fructosidase. Affinity labeling of the active site. 1 9

The degrees of autolysis attained by five different genera of filamentous fungi during an incubation period of 60 days, under the same culture conditions were: 87.3% for Penicillium oxalicum; 65.9% for Neurospora crassa; 62.7% for Polystictus versicolor; 51.7% for Aspergillus niger and 23.5% for Nectria galligena. N. crassa, A. niger and P. versicolor reached the end of the autolysis during this incubation period (60 days), whereas P. oxalicum and N. galligena did not. The excretion of the lytic enzymes beta-N-acetylglucosaminidase, beta -1-3 glucanase, chitinase, invertase and acid phosphatase into the culture medium during growth and autolysis was investigated. The excretion of these enzymes was consistent with the degree of autolysis reached, the maximum excretion belonging to P. oxalicum and the minimum to N. galligena. The N. crassa invertase was excreted into the culture liquid at levels very much higher than the other enzymes studied, and at levels very much higher than the invertases excreted by the other fungi.
Mycopathologia 1976 Dec 10
PMID:Lytic enzymes in the autolysis of filamentous fungi. 1 4

The use of a commercial oscillating-tube densitometer with an accuracy of 4 . 10(-7) g/cm3 for the determination of enzyme-kinetics constants is tested. This method is applied to the investigation of the influence of vitamin C (sodium ascorbate) on the glycolytic enzymes invertase, dextransucrase and dextranase. Invertase is inhibited uncompetitively, dextransucrase non-competitively. There is no significant effect of the vitamin on dextranase. The comparison of the mechanisms of the three enzymes suggests that only those reaction steps are inhibited by vitamin C in which fructose is released from the enzyme.
J Biochem Biophys Methods 1979 Dec
PMID:The use of an oscillating-tube densitometer as a tool in enzyme kinetics. Determination of the influence of sodium ascorbate on invertase, dextransucrase and dextranase. 9 45

Intestinal mucosa from 40 patients obtained by fiber-endoscopic biopsy was assayed for disaccharidases to determine suitability of this tissue for assay. The combined specimens from each patient provided 4.7-38.7 mg of tissue, adequate in all instances for duplicate determinations of protein, lactase, sucrase, and maltase. Tissue remained for assays of palatinase in 39 instances, trehalase and cellobiase in 37, and alkaline phosphatase in 22 cases. Twenty-four subjects had normal lactose tolerance tests and normal sucrase/lactase ratios. Thirteen patients with abnormal oral lactose tolerance tests were identified as having a primary low lactase activity on the basis of elevated sucrase/lactase ratios. This ratio was most helpful in making the diagnosis of a primary low lactase, since the mucosal specimens were not obtained from comparable areas. Tissue from three subjects with an abnormally low maltase was unsuitable for diagnosis. Endoscopic biopsy of mucosa appears to be satisfactory for disaccharidase assays in most instances.
Am J Dig Dis 1978 Dec
PMID:Adequacy of endoscopic biopsy specimens for disaccharidase assays. 10 20

Invertase, extracted from broken cells of Saccharomyces cerevisiae X-2180 mm2 mannan mutant, was separated into a fraction insoluble in 75% ammonium sulfate (P75 invertase, 36% carbohydrate) and a soluble fraction (S75 invertase, 53% carbohydrate). The latter reacted with antibodies specific for the alpha 1 leads to 6-linked mannose of the mannoprotein outer chain, whereas the P75 invertase failed to react with this antiserum although it did react with serum against terminal alpha 1 leads to 3-linked mannose units that are characteristic of the mannoprotein core. A bacterial endo alpha 1 leads to 6-mannanase removed the outer chains from the S75 invertase and converted it to a form that was similar in electrophoretic and immunochemical properties to the P75 invertase, whereas the endomannanase had little effect on the latter invertase. The results suggest that the P75 invertase is a form of the enzyme to which only the core oligosaccharide units had been added, and the S75 invertase represents an enzyme fraction to which the polysaccharide outer chains were also attached. A strong anomeric PMR signal for unsubstituted alpha 1 leads to 6-linked mannose in the S75 invertase, and a much reduced signal in the P75 invertase and endomannanase-digested S75 invertase, support these conclusions. Endo-N-acetyl-beta-glucosaminidase digestion of the S75 and P75 invertases, as well as of a purified wild type yeast invertase, produced an apparently identical series of 3 to 4 carbohydrate-containing proteins that were separable by polyacrylamide gel electrophoresis in sodium dodecyl sulfate but that migrated as a single band on isoelectric focusing. The bands ranged from about 63,000 to 69,000 daltons and differed by the size of one or more carbohydrate core units each of 15 mannoses and 1 N-acetylglucosamine. The results suggest that the external invertase molecules contain some core units without attached outer chains, and that the cells contain a precursor form of the enzyme to which only the core units have been added. In support of this conclusion, PMR spectra and chromatographic patterns show that the core fragments from the P75, S75, and wild type invertases are essentially identical.
J Biol Chem 1979 Dec 10
PMID:Carbohydrate structure of yeast invertase. Demonstration of a form with only core oligosaccharides and a form with completed polysaccharide chains. 11 81

To better understand the pathogenesis of infantile viral gastroenteritis, we studied Na+ and Cl- fluxes in vitro in short-circuited jejunal epithelium from 8-10-day-old piglets after infection with a standard dose of human rotavirus given via nasogastric tube. 11 infected piglets, all of whom became ill, were compared with 9 uninfected, healthy litter-mates. When killed 72 h after infection, intestinal villi were shorter and crypts deeper (P less than 0.025) in duodenum, upper jejunum, and mid-small intestine, but not ileum in infected piglets. Virus antigen was seen by fluorescence microscopy in occasional jejunal villus tip cells in only four infected piglets and no controls at 72 h. Net Na+ and Cl- fluxes did not differ from noninfected litter-mate controls under basal conditions, but response to glucose was blunted in infected piglets (P less than 0.001). Theophylline stimulated net Cl- secretion in both infected and control animals, and cyclic AMP concentration in isolated jejunal villus enterocytes did not differ significantly. In isolated jejunal villus enterocytes of infected piglets, thymidine kinase activity increased (P less than 0.001), and sucrase activity decreased (P less than 0.001). We conclude that in this invasive enteritis caused by a major human viral pathogen, glucose-coupled Na+ transport is impaired in the jejunum at a time when the villus epithelium shows enzyme characteristics of crypt epithelium, and when little or no virus is present. These findings are identical to those occurring in an invasive coronavirus enteritis of piglets but differ markedly from those seen with enterotoxigenic diarrhea.
J Clin Invest 1977 Dec
PMID:Human rotavirus enteritis induced in conventional piglets. Intestinal structure and transport. 19 22

Streptococcus mutans has been shown to produce extracellular invertase, dextransucrase, and levansucrase. The purpose of this work was to study the relative quantities of these enzymes in pure culture supernatant, and in samples from commonly used purification methods. The strain "Ingbritt" was selected because it is a well-defined human strain, available, and with well-known growth requirements. The samples were incubated with sucrose for the determination of free monohexoses, and the polysaccharide from ethanol precipitation was hydrolyzed as previously described. In cell supernatant the inversion effect exerted 75% of total sucrolytic power, the dextransucrase 20% and the levansucrase 5%. No method, tested in this work, could separate all the activities completely.
Scand J Dent Res 1978 Dec
PMID:Combined extracellular sucrolytic enzyme power from a strain of Streptococcus mutans, and purification results. 28 69

The activities of ornithine aminotransferase, sucrase and acid and alkaline phosphatases have been studied throughout sporulation in Saccharomyces cerevisiae. The same enzymes were monitored during synchronous vegetative growth. Each of these enzymes has been demonstrated to increase in a 'step' manner during both growth and sporulation. Alkaline phosphatase increased in a two-step manner whereas the others increased in a single step. The times of increase of these enzymes formed a similar sequence during both sporulation and growth. It has been proposed that these enzymes are under a common mechanism of control during growth and sporulation and that the sequence of enzyme appearance may be used as markers of the sporulation process.
J Gen Microbiol 1978 Dec
PMID:The use of step enzymes as markers during meiosis and ascospore formation in Saccharomyces cerevisiae. 37 Mar 42

After isolation of the hamster small intestine, the effects of a continuous infusion of cholecystokinin-pancreozymin (CCK-PZ) are studied. Several enzymic activities are measured in the intestinal lumen and compared with the level found in the intestinal homogenate. During CCK-PZ infusion we observed a direct stimulation of Paneth cells associated with an increase of lysozyme activity. Furthermore this work confirms the stimulating effect of CCK-PZ on alkaline phosphatase and amino-peptidase. Maltase and sucrase levels were unaffected. The liberation of the hydrolase of the brush border in the intestinal lumen is negligible and cannot be considered as a true secretion. Only granule content of Paneth cells is actually secreted. However, biochemical data, corroborated by morphological results, suggest that Paneth cell secretion could in part be absorbed on the outer surface of the brush border.
Acta Hepatogastroenterol (Stuttg) 1979 Dec
PMID:Comparative effects of CCK-PZ on certain intestinal hydrolases in the mucosa and in the luminal content of the hamster jejuno-ileum. 39 57


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