Gene/Protein Disease Symptom Drug Enzyme Compound
Pivot Concepts:   Target Concepts:
Query: EC:3.2.1.31 (beta-glucuronidase)
 7,680 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

A number of studies, mostly performed ex vivo, suggest that lysosomes are involved in apoptosis as a result of a release of their cathepsins into the cytosol. These enzymes could then contribute to the permeabilization of the outer mitochondrial membrane; they could also activate effector caspases. The present study aims at testing whether the membrane of liver lysosomes is disrupted during Fas-mediated cell death of hepatocytes in vivo, a process implicated in several liver pathologies. Apoptosis was induced by injecting mice with aFas (anti-Fas antibody). The state of lysosomes was assessed by determining the proportion of lysosomal enzymes (beta-galactosidase, beta-glucuronidase, cathepsin C and cathepsin B) present in homogenate supernatants, devoid of intact lysosomes, and by analysing the behaviour in differential and isopycnic centrifugation of beta-galactosidase. Apoptosis was monitored by measuring caspase 3 activity (DEVDase) and the release of sulfite cytochrome c reductase, an enzyme located in the mitochondrial intermembrane space. Results show that an injection of 10 microg of aFas causes a rapid and large increase in DEVDase activity and in unsedimentable sulfite cytochrome c reductase. This modifies neither the proportion of unsedimentable lysosomal enzyme in the homogenates nor the behaviour of lysosomes in centrifugation. Experiments performed with a lower dose of aFas (5 microg) indicate that unsedimentable lysosomal hydrolase activity increases in the homogenate after injection but with a marked delay with respect to the increase in DEVDase activity and in unsedimentable sulfite cytochrome c reductase. Comparative experiments ex vivo performed with Jurkat cells show an increase in unsedimentable lysosomal hydrolases, but much later than caspase 3 activation, and a release of dipeptidyl peptidase III and DEVDase into culture medium. It is proposed that the weakening of lysosomes observed after aFas treatment in vivo and ex vivo results from a necrotic process that takes place late after initiation of apoptosis.
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PMID:Lysosomes and Fas-mediated liver cell death. 1712 11

Sulfite oxidase (SO), one of the known molybdenum co-factor-containing enzymes, plays important roles in diverse metabolic processes such as sulfur detoxification and purine catabolism in mammals. But much less is known about the expression and regulatory characterization of sulfite oxidase gene in higher plants. In this report, expression of Arabidopsis SO is characterized in detail by semi-quantitative RT-PCR and histochemical staining. The results showed that the transcripts of AtSO were predominantly detected in Arabidopsis aerial tissues including stems, young leaves, young inflorescences and immature siliques at higher level, but in roots with a lower level. To monitor AtSO expression in plant, the promoter region containing a 1 562-bp genomic sequence from AtSO was isolated and analyzed using methods of bioinformatics. Basing on the distribution of beta-glucuronidase (GUS) activities shown by histochemical staining in transgenic Arabidopsis plants harboring the promoter-uidA fusion construct, it can be concluded that AtSO is expressed mainly in the green tissues/organs in a light-dependent way. In addition, its expression is up-regulated during sulfite treatment. The information from this study may provide useful clue for further functional analysis of plant SO homologs during light-induced development of leaf tissue and/or excessive sulfite/SO(2) gas stresses in higher plants.
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PMID:Isolation and functional analysis of sulfite oxidase gene AtSO promoter from Arabidopsis thaliana. 1796 39