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)

Glycosidases and glycosyltransferases were electrophoresed in the presence of sodium dodecyl sulfate (SDS) in a thin-layer gel supported by a glass plate, treated with the nonionic detergent Triton X-100, and specifically stained for the sugar-releasing activity of these enzymes. Staining is based on conversion of monosugars or a sugar phosphate to glucose-6-phosphate by the appropriate intermediary enzymes, reduction of NADP+ to NADPH, and accumulation of reduced Nitroblue Tetrazolium in the gel. Among the enzymes tested, alpha-glucosidase, beta-glucosidase and beta-mannosidase could not be renatured, whereas beta-fructofuranosidase and alpha-mannosidase could be renatured unless heated before electrophoresis. Sucrose phosphorylase, glucosyltransferase and fructosyltransferase, which are single-peptide proteins with no cystine bond, could be renatured even after pretreatment with SDS and/or mercaptoethanol at 100 degrees C for 10 min. However, exclusive heating remarkably decreased the activities of these enzymes. Two-dimensional separation of the five renaturable enzymes was done in a single thin-layer gel, using SDS-electrophoresis in the first dimension and isoelectric focusing in the second dimension.
...
PMID:Renaturation and activity staining of glycosidases and glycosyltransferases in gels after sodium dodecyl sulfate-electrophoresis. 752 70

Trehazolin, a new trehalase inhibitor isolated from the culture broth of Micromonospora, was reported to be a highly specific inhibitor for porcine and silk worm trehalases with IC50 values of 5.5 x 10(-9) and 3.7 x 10(-9) M, respectively (O. Ando, H. Satake, K. Itoi, A. Sato, M. Nakajima, S. Takashi, H. Haruyama, Y. Ohkuma, T. Kinoshita, and R. Enokita (1991) J. Antibiot. 44, 1165-1168). We also found that trehazolin is a very powerful and quite specific inhibitor against purified pig kidney trehalase, giving an IC50 value of 1.9 x 10(-8) M. Lineweaver-Burk plots showed that this compound was a competitive inhibitor of the trehalase. However, even at concentrations of 200 micrograms/ml, trehazolin did not inhibit the rat intestinal maltase or sucrase, yeast alpha-glucosidase or almond beta-glucosidase. Validoxylamine A and validamycin A, two other trehalase inhibitors, showed potent competitive inhibition against purified pig kidney trehalase, with IC50 values of 2.4 x 10(-9) and 2.5 x 10(-4) M, respectively. On the other hand, validoxylamine A was almost inactive against rat intestinal sucrase and maltase, with some inhibition being observed at millimolar concentration. A number of other glucosidase inhibitors, such as MDL 25637, castanospermine, and deoxynojirimycin were also tested against the purified trehalase and showed reasonable inhibitory activity.
...
PMID:Inhibitors of pig kidney trehalase. 786 39

Duodenal biopsies were collected from 38 subjects (24 female and 14 male) ranging in age from 55 to 91 years. Evidence of bacterial contamination of the small bowel (BCSB) was sought at the same time by bacterial culture of duodenal aspirates and by hydrogen and [14C]glycocholic acid breath tests; subjects were considered to be positive for BCSB if any one of the three tests was abnormal. Biopsies were analyzed for six brush-border membrane enzyme activities: maltase, sucrase, lactase, alkaline phosphatase, leucine aminopeptidase, and alpha-glucosidase. Analysis of covariance with age as the covariate indicated no significant effect of age on the specific activities of these enzymes. Mucosal Na(+)-dependent glucose transport was quantified in brush-border membrane vesicles prepared from the biopsies. In all groups, glucose transport at 20-30 sec was greater (ranging from mean values of 2.45 to 3.66 times) than at 45 min, consistent with Na(+)-coupled glucose transport, and no significant effect of age was observed. BCSB had no significant effect on specific activities of any of the duodenal mucosal hydrolases but was associated with reduced (P = 0.05) brush-border glucose transport. None of the variables studied was significantly affected by the gender of subjects. In conclusion, these biochemical data do not support the contention that reduced capacity for carbohydrate absorption in the elderly is explained by reductions in duodenal brush-border mucosal disaccharidase activities or glucose transport.
...
PMID:Duodenal brush-border mucosal glucose transport and enzyme activities in aging man and effect of bacterial contamination of the small intestine. 844 69

Two isoenzymes of maltase (EC 3.2.1.20) were purified to homogeneity from Candida albicans. Isoenzymes I and II were found to have apparent molecular masses of 63 and 66 kDa on SDS/PAGE with isoelectric points of 5.0 and 4.6 respectively. Both isoenzymes resembled each other in similar N-terminal sequence, specificity for the alpha(1-->4) glycosidic linkage and immune cross-reactivity on Western blots using a maltase II antigen-purified rabbit antibody. Maltase was induced by growth on sucrose whereas beta-fructofuranosidase activity could not be detected under similar conditions. Maltase I and II were shown to be unglycosylated enzymes by neutral sugar assay, and more than 90% of alpha-glucosidase activity was recoverable from spheroplasts. These data, in combination with other results from this laboratory [Geber, Williamson, Rex, Sweeney and Bennett (1992) J. Bacteriol. 174, 6992-6996] showing lack of a plausible leader sequence in genomic or mRNA transcripts, suggest an intracellular localization of the enzyme. To establish further the mechanism of sucrose assimilation by maltase, the existence of a sucrose-inducible H+/sucrose syn-transporter was demonstrated by (1) the kinetics of sucrose-induced [14C]sucrose uptake, (2) recovery of intact [14C]sucrose from ground cells by t.l.c. and (3) transport of 0.83 mol of H+/mol of [14C]sucrose. In total, the above is consistent with a mechanism whereby sucrose is transported into C. albicans to be hydrolysed by an intracellular maltase.
...
PMID:Role of maltase in the utilization of sucrose by Candida albicans. 848 4

The uptake kinetics of sugars present in wheat doughs and alpha-glucosidase as well as beta-fructosidase activities were determined in different strains of yeasts and lactic acid bacteria. These strains were previously selected according to their breadmaking quality. Saccharomyces cerevisiae (P6), Candida guilliermondii (P40), Lactobacillus plantarum (B31 and La18) and L. brevis (B21) showed good performance, while Sacch. fructuum (P43), L. cellobiosus (B37) and Enterococcus faecium (B11) yielded bread of lower quality. Leuconostoc mesenteroides (B10), when used in combination with other strains led also to high quality starters. All yeast strains used assimilated glucose, fructose and maltose, exhibiting saturable kinetics. Lactic acid bacteria showed saturable kinetics only for hexoses, whereas disaccharide uptake was linear. Sacch. cerevisiae, Leuconostoc mesenteroides, L. brevis and L. plantarum (B31) displayed better sugar uptake properties. For all the strains used alpha-glucosidase and beta-fructosidase activities were detected. The highest specific activities were found for Sacch. cerevisiae, C. guilliermondii and L. plantarum (B31). These results indicate good correlation between the parameters evaluated and the breadmaking potential of the microorganisms.
...
PMID:Sugar uptake and involved enzymatic activities by yeasts and lactic acid bacteria: their relationship with breadmaking quality. 849 88

To examine the postnatal development of equine small intestine, biopsy specimens of jejunal mucosa from 8 ponies, between 6 and 28 weeks old, were subjected to analytical subcellular fractionation and assay of organelle marker enzymes. Fractionation revealed a reduction in the particulate brush border component of beta-galactosidase (lactase) activity between 6 and 28 weeks, and a corresponding increase in soluble activity, although the reduction in mean specific activity was not significant. There also was a decrease in the proportion of brush border to soluble aminopeptidase N activity, a relative loss of brush border gamma-glutamyltransferase activity, and a considerable decrease in the specific activity of alkaline phosphatase throughout the gradient fractions. In contrast, there were marked increases in activities of alpha-glucosidase (maltase) and sucrase in the older ponies, accompanied by considerable changes in the intracellular distribution of particulate alpha-glucosidase activity, which was predominantly associated with endoplasmic reticulum at 6 weeks, whereas the large increase in activity observed by 28 weeks was clearly associated with the brush border. The modal density of brush borders also increased with age, suggestive of an increase in the glycoprotein-to-lipid ratio of the microvillar membrane. In contrast to these brush border changes, there was relatively little alteration in the activities or density distributions of marker enzymes for endoplasmic reticulum, basolateral membranes, mitochondria, or lysosomes. These findings indicate that maturation of equine intestinal epithelium during the first few months of life results in major changes in the properties and enzyme composition of enterocyte brush borders.
...
PMID:Subcellular biochemical changes during the development of the small intestine of pony foals. 853 83

Cells of the fission yeast Schizosaccharomyces pombe were permeabilized by treatment with toluene-ethanol. The permeabilized cells lost the bulk of the internal trehalose pool while most of the alkaline phosphatase, invertase, alpha-glucosidase, or neutral trehalase activities located inside the cells remained unaffected. This system was used as an in situ assay to determine the involvement of trehalose in enzyme protection during thermal treatments. The addition of trehalose to suspensions of permeabilized cells resulted in a sugar-dependent thermoprotection of the internal marker enzymes. This approach demonstrates that in whole cells of the fission yeast trehalose plays a physiological role as a protective molecule against thermal denaturation of cellular enzymes.
...
PMID:Increased thermal stability of the enzyme content in permeabilized whole cells from the fission yeast Schizosaccharomyces pombe by exogenous trehalose and other compounds. 859 Apr 7

Antiobesity and antidiabetic actions of the alpha-glucosidase inhibitor AO-128 were examined using genetically obese-diabetic rats, Wistar fatty. Ten-week-old, male fatty rats were kept on CE-2 diet containing 10 or 25 ppm of AO-128 for 4 weeks. The average drug intake was calculated to be 0.74 or 1.78 mg/kg/day from the average food intake, respectively. The intestinal maltase and sucrase activities were decreased by AO-128 in a dose-related fashion. Food intake of fatty rats treated with AO-128 was decreased throughout the experiment. This decrease in food intake could hardly be explained only by diarrhea which occurred for the first 5 days of the administration of AO-128. AO-128 normalized hyperglycemia and markedly reduced hypertriglyceridemia and hyperinsulinemia in fatty rats. In addition, AO-128 decreased body weight gain, food efficiency, epididymal adipose tissue weight, carcass weight, and body fat deposition. These findings indicate that AO-128 may be useful for treating human obesity and diabetes.
...
PMID:AO-128, alpha-glucosidase inhibitor: antiobesity and antidiabetic actions in genetically obese-diabetic rats, Wistar fatty. 869 66

The objective of this study was to investigate the effects of L-arabinose on intestinal alpha-glucosidase activities in vitro and to evaluate its effects on postprandial glycemic responses in vivo. L-Arabinose inhibited the sucrase activity of intestinal mucosa in an uncompetitive manner (Ki, 2 mmol/L). Neither the optical isomer D-arabinose nor the disaccharide L-arabinobiose inhibited sucrase activity, whereas D-xylose was as potent as L-arabinose in inhibiting this activity. L-Arabinose and D-xylose showed no inhibitory effect on the activities of intestinal maltase, isomaltase, trehalase, lactase, and glucoamylase, or pancreatic amylase. In contrast, a known alpha-glucosidase inhibitor, acarbose, competitively inhibited (Ki, 1.1 mumol/L) sucrase activity and also inhibited intestinal maltase, glucoamylase, and pancreatic amylase. L-Arabinose suppressed the increase of blood glucose after sucrose loading dose-dependently in mice (ED50, 35 mg/kg), but showed no effect after starch loading. The suppressive effect of D-xylose on the increase of blood glucose after sucrose loading was 2.4 times less than that of L-arabinose, probably due to intestinal absorption of the former. Acarbose strongly suppressed glycemic responses in both sucrose loading (ED50, 1.1 mg/kg) and starch loading (ED50, 1.7 mg/kg) in mice. L-Arabinose suppressed the increase of plasma glucose and insulin in rats after sucrose loading, the suppression of the former being uninterruptedly observed in mice for 3 weeks. Thus, the results demonstrated that L-arabinose selectively inhibits intestinal sucrase activity in an uncompetitive manner and suppresses the glycemic response after sucrose ingestion by inhibition of sucrase activity.
...
PMID:L-arabinose selectively inhibits intestinal sucrase in an uncompetitive manner and suppresses glycemic response after sucrose ingestion in animals. 893 41

A point mutation in the cDNA of human intestinal sucrase-isomaltase has been recently identified in phenotype II of congenital sucrase-isomaltase deficiency. The mutation results in a substitution of glutamine by proline at position 1098 (Q1098P) in the sucrase subunit. Expression of this mutant sucrase-isomaltase cDNA in COS-1 cells results in an accumulation of sucrase-isomaltase in the ER, intermediate compartment and the cis-Golgi cisternae similar to the accumulation in phenotype II intestinal cells. An interesting feature of the Q1098P substitution is its location in a region of the sucrase subunit that shares striking similarities with the isomaltase subunit and other functionally related enzymes, such as human lysosomal acid alpha-glucosidase and Schwanniomyces occidentalis glucoamylase. We speculated that the Q-->P substitution in these highly conserved regions may result in a comparable accumulation. Here we examined this hypothesis using lysosomal alpha-glucosidase as a reporter gene. Mutagenesis of the glutamine residue at position 244 in the homologous region of alpha-glucosidase to proline results in a protein that is neither transported to the lysosomes nor secreted extracellularly but accumulates in the ER, intermediate compartment and cis-Golgi as a mannose-rich polypeptide similar to mutant sucrase-isomaltase in phenotype II. We propose that the Q1098P and Q244P mutations (in sucrase-isomaltase and alpha-glucosidase, respectively) generate structural alterations that are recognized by a control mechanism, operating beyond the ER in the intermediate compartment or cis-Golgi.
...
PMID:A mutation in a highly conserved region in brush-border sucrase-isomaltase and lysosomal alpha-glucosidase results in Golgi retention. 909 38


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

---