Gene/Protein Disease Symptom Drug Enzyme Compound
Pivot Concepts:   Target Concepts:
Query: EC:3.2.1.20 (alpha-glucosidase)
 4,237 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

The alpha-glucosidase inhibitor bromoconduritol (6-bromo-3,4,5-trihydroxycyclohex-1-ene) inhibits trimming of the innermost glucose residue from the Glc3Man9GlcNAc2 precursor of high-mannose and complex oligosaccharides. This inhibition occurs both in intact cells and with a microsomal enzyme preparation. The formation of lipid-linked oligosaccharides was increased in glucosidase-inhibited cells. Inhibition of transfer of high-mannose oligosaccharides to protein was not observed. In bromoconduritol-treated virus-infected cells, trimming of mannose can occur despite incomplete removal of glucose. The glucosylated high-mannose oligosaccharides GlcMan9GlcNAc, GlcMan8GlcNAc, and GlcMan7GlcNAc were released from viral glycoproteins after digestion with Pronase and endo-beta-N-acetylglucosaminidase H. The formation of complex oligosaccharides was concomitantly inhibited. The release of infectious fowl plague virus particles (an influenza virus) was inhibited from bromoconduritol-treated infected chicken-embryo cells.
 ...
PMID:Inhibition of formation of complex oligosaccharides by the glucosidase inhibitor bromoconduritol. 675 22

The amounts of lactase (EC 3.2.1.23), sucrase (EC 3.2.1.48), maltase (EC 3.2.1.20), microvillus aminopeptidase (microsomal EC3.4.11.2), and dipeptidyl peptidase IV (EC 3.4.14.X) in biopsies from proximal jejunum and distal ileum were studied by quantitative crossed immunoelectrophoresis and enzymatic assays in obese patients one and six months after jejunoileal bypass operation and compared with peroperative levels. They were related to DNA and protein content. The protein/DNA ratio fell 28-43% postoperatively. Except for ileal lactase and sucrase all enzymes showed decreased levels when expressed per mg protein and an even more pronounced decrease when related to DNA. Lactase and sucrase levels in ileum were increased or unchanged. A constant correlation between the amount of immunoreactive enzyme protein and enzymatic activity was shown for all enzymes except maltase. The results suggest that the bypass operation is followed by an increased amount of enterocytes devoid of or low in enzymatic activity and protein content. The amounts of lactase and sucrase in ileum are increased in relation to the other enzymes. No immunoreactive enzymes with zero or depressed activity were detected.
 ...
PMID:Immunoelectrophoretic studies on human small intestinal brush border proteins: cellular alterations in the levels of brush border enzymes after jejunoileal bypass operation. 742 30

It has been reported that aortic homografts that have been cryopreserved before transplantation remain viable longer as an allograft than tissue stored at 4 degrees C in an antibiotic solution. In the present study, we tested the hypothesis that storage of cardiac valve tissue by cryopreservation or by antibiotic preservation may alter the metabolic status of the tissue. Initially, we collected aortic valves composed of cardiac tissue, aortic root, and valvular tissue from cadaver donors. These specimens were divided into three equal portions, and one portion was analyzed before storage while the other two parts were stored for 3 weeks at either 4 degrees C in an antibiotic solution or at -196 degrees C in liquid nitrogen. All specimens were examined with regard to the following parameters: tissue structure, tissue viability, cell proliferative capacity, metabolic function, and identification of cell-specific antigens. We found no significant alterations in the structure of any of the three tissue components after antibiotic preservation or cryopreservation; however, cell viability and cell number were decreased in all three groups. All tissue samples grew in culture before storage. When we compared activities of the following organellar marker enzymes--lysosomal acid lipase, plasma membrane 5' nucleotidase, mitochondrial cytochrome oxidase, and microsomal neutral alpha-glucosidase--we observed no major differences between tissues stored by either technique. In addition, we observed no loss of enzymic activity as a result of storage. Finally, when cell lines isolated from each tissue specimen were incubated with monoclonal antibodies against cell-specific antigens in an immunoperoxidase assay, all the cell cultures proved to be endothelial cells. These results suggest that although cardiac valve tissue stored by cryopreservation or by antibiotic preservation retained its normal structure and metabolic capabilities, both storage techniques produced significant decreases in cell numbers and viability. However, only endothelial cells from tissue stored by cryopreservation retained the capacity to proliferate in vitro. These findings have important implications for the function of aortic homografts transplanted after storage.
 ...
PMID:Biochemical and cellular characterization of cardiac valve tissue after cryopreservation or antibiotic preservation. 766 4

Microcystine-YR (20 ug/kg bodyweight) and 8 ug/kg bodyweight of nodularin were intraperitoneally injected to 90 female Swiss mice. After 15, 30, 60 min and 24 h the changes were observed in the activity of some glucosidases in the complete cell homogenate and in the lysosomal, microsomal and cytosol fraction. Significant differences were connected with the time after administration of poison and with the cellular fraction. Nodularin induces the activity of beta-D-glucuronidase, alpha-glucosidase, lysosomal esterase and N-acetyl-glucosaminidase and influenced on the labilization of endoplasmatic reticulum membranes. Microcystine-YR inhibited the biosynthesis of glucosidases and revealed a destructive effect on membranes of lysosomes and endoplasmatic reticulum.
 ...
PMID:Influence of microcystine-YR and nodularin on the activity of some glucosidases in mouse liver. 1081 50

1. The activities of lysosomal enzymes in the cortexes and medullas and the principal subcellular fractions of rat kidney were measured. 2. A method is described for the isolation of rat-kidney lysosomes and a detailed analysis of the enzymic composition of the lysosomes is reported. Enzyme analysis of the other principal subcellular fractions is included for comparison. 3. Studies of the distribution of alpha-glucosidase showed that the lysosomal fraction contained only 10% of the total enzyme activity. The microsomal fraction contained most of the particulate alpha-glucosidase. Lysozyme was concentrated mainly in the lysosomal fraction with only small amounts present in the microsomal fraction. Lysosomal alpha-glucosidase had optimum pH5 whereas the microsomal form had optimum pH6. Both lysosomal and microsomal lysozyme had optimum pH6.2. 4. The stability of lysosomal suspensions was studied. Incubation at 37 degrees and pH7 resulted in first an increased availability of enzymes without parallel release of enzyme. This was followed by a second stage during which the availability of enzymes was closely related to the release of enzymes. These changes were closely paralleled by changes in light-scattering properties of lysosomes. 5. The latent nature of the alpha-glucosidase and lysozyme of intact kidney lysosomes was demonstrated by their graded and parallel release with other typical lysosomal enzymes. 6. Isolated lysosomes were unstable at pH values lower than 5, most stable at pH6-7 and less stable at pH 8-9. Lysosomes were not disrupted when the osmolarity of the suspending medium was decreased from 0.6m to 0.25m. 7. The discussion compares the properties and composition of kidney lysosomes, liver lysosomes and the granules of macrophages. 8. The possible origin of the lysozyme in kidney lysosomes by reabsorption of the lysozyme in blood is discussed.
 ...
PMID:RAT-KIDNEY LYSOSOMES: ISOLATION AND PROPERTIES. 1434 9


<< Previous 1 2 3