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

Sertoli cells were isolated from prepubertal mice and cultured in serum-free medium to determine whether they secrete glycoproteins containing mannose 6-phosphate (M6P). Assays of the conditioned medium for lysosomal enzyme precursors, which typically bear the M6P recognition marker, indicated that Sertoli cells selectively secreted beta-N-acetylhexosaminidase and alpha-mannosidase, but not beta-glucuronidase or beta-galactosidase. Sertoli cells were labeled metabolically with [35S]methionine and the conditioned medium was fractionated on a cation-independent M6P receptor affinity column. Most of the secreted proteins did not bind to the column (peak A); however, approximately 10% of the radioactivity eluted as a low-affinity fraction (peak B), and 5-11% of the recovered cpm bound to the column and were eluted with 2.5 mM M6P (peak C). The radiolabeled proteins in each fraction were analyzed by one- and two-dimensional electrophoresis and fluorography. Two protein bands with molecular weights of 30,000 and 35,000 were present in peak B. Peak C contained at least ten M6P-containing glycoproteins with molecular weights between 30,000 and 135,000 and isoelectric points < 6.5. The 35,000-molecular-weight constituent prominent both in peaks B and C was identified as procathepsin L by immunoprecipitation with a specific antibody. When pachytene spermatocytes and round spermatids were cultured overnight in the presence of peak C glycoproteins radiolabeled with 125I, both germ cell types accumulated these Sertoli M6P-glycoproteins by a receptor-mediated process that was specifically inhibited by M6P. The Sertoli M6P-glycoproteins taken up by germ cells were processed to lower molecular weight forms. These results provide evidence that M6P receptors on the surface of spermatogenic cells endocytose secrete glycoproteins that are likely to be present in the seminiferous epithelium.
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PMID:Mouse Sertoli cells secrete mannose 6-phosphate containing glycoproteins that are endocytosed by spermatogenic cells. 828 71

The genetic mucopolysaccharidoses (MPS) are a family of lysosomal storage diseases resulting from defective catabolism of glycosaminoglycans (GAGs). Echocardiographic abnormalities in dogs with MPS type VII (Sly syndrome, beta-glucuronidase deficiency) included mitral valve thickening and insufficiency, large aortic dimensions in both the long and short axes, and thickened aortic valves. Grossly, at post mortem examination, there was nodular thickening of the mitral valve, a prominent ductus diverticulum, and a dilated aorta with thickened walls. Histologically, cytoplasmic vacuolation was seen in cells of the mitral valves, coronary arteries, and aorta. By electron microscopy, the cells of the mitral valve were packed with electron-lucent cytoplasmic vacuoles. The mean residual activity of beta-glucuronidase in the aorta and myocardium was <1% of normal, the mean hexosaminidase A activity >2. 5 times normal, and the mean GAG concentrations more than twice normal. In three MPS VII dogs that received heterologous BMT at 6 weeks of age, the echocardiographic abnormalities were improved, and the histopathologic and ultrastructural pathology was reduced. In the aorta and myocardium, the mean beta-glucuronidase activity of the BMT group was 4.5% and 11% of normal, respectively, and the hexosaminidase A activity and GAG concentrations were normalized. Bone Marrow Transplantation (2000) 25, 1289-1297.
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PMID:Effects of bone marrow transplantation on the cardiovascular abnormalities in canine mucopolysaccharidosis VII. 1087 35

During fasting of animals, there is decreased content of skin glycosaminoglycans (GAGs) accompanied by decrease in their biosynthesis. Since tissue GAG content depends on both synthesis and degradation of these molecules, we asked whether fasting affects the activity of several tissue glycosidases. Therefore we measured the activity of skin neutral and acidic endoglycosidases, some exoglycosidases: beta-N-acetylhexosaminidase [EC 3.2.1.30], beta-galactosidase [EC 2.1.23], beta-glucuronidase [EC 3.2.1.31], alpha-iduronidase [EC 3.2.1.76], and two sulfatases: arylsulfatase B [EC 3.1.6.1] and 6-sulfatase [EC 3.1.6.14] in the skin of control and fasted rats. Although fasting was accompanied by distinct decrease in the activity of most neutral endoglycosidases, no characteristic changes in the activity of exoglycosidases were found. In contrast, we found that fasting is associated with increase in the activity of acidic endoglycosidases (of lysosomal origin) which degraded hyaluronic acid, chondroitin-4-sulfate, chondroitin-6-sulfate and heparin. The same GAGs were decreased in the skin of fasted rats. Our data suggest that the phenomenon is a result of increased intracellular degradation of these molecules. Therefore, not only decreased biosynthesis of GAGs during fasting, but also increased their intracellular degradation may contribute to decrease in GAG skin content.
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PMID:Glycosaminoglycan-degrading enzymes in the skin of fasted rats. 1195 38

Fasciola hepatica secretes proteolytic enzymes and other molecules that are essential for host penetration and migration. This mixture may include enzymes required for the degradation of supramucosal gels, which defend epithelial surfaces against pathogen entry. These contain hydrated mucins that are heavily glycosylated. Excretory-secretory products (ES) from F. hepatica were examined for a range of glycosidase activities, using synthetic 4-methylumbelliferyl glycosides as substrates. The ES product contained at least 8 different glycosidase activities, the most abundant of which were beta-N-acetylhexosaminidase, beta-galactosidase and beta-glucosidase. Alpha-fucosidase, beta-glucuronidase, alpha-galactosidase, alpha-mannosidase and neuraminidase were also present. Beta-N-acetylhexosaminidase and beta-galactosidase were present in multiple isoforms (at least 4), whereas beta-glucosidase appeared to exist as one isoenzyme with a pI < 3.8. All three enzymes had acidic pH optima (4.5-5.0). Ovine small intestinal mucin was degraded by ES at pH 4.5 or 7.0, with or without active cathepsin L, the major protease found in F. hepatica ES. The ability of F. hepatica ES to degrade mucin in the presence or absence of active cathepsin L suggests that cathepsin L is not essential for mucin degradation. The abundance of beta-galactosidase and beta-hexosaminidase in ES supports a role for these enzymes in mucin degradation.
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PMID:Glycosidase activity in the excretory-secretory products of the liver fluke, Fasciola hepatica. 1552 35


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