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)

Immunoelectron microscopic localization of lysosomal and peroxisomal enzymes in the eosinophil leukocytes of rat intestinal mucosa was studied by use of rabbit antibodies to the enzymes coupled to protein A-gold complex. Gold particle labeling for the lysosomal enzymes, beta-glucuronidase and cathepsin D, was present on specific granules, with a heavy concentration on their paracrystalline cores. The peroxisomal enzymes, acyl-CoA oxidase and catalase, were also found on these granules. The double labeling procedures using two different combination of anti-acyl-CoA oxidase and anti-beta-glucuronidase or anti-catalase and anti-cathepsin D revealed that these enzymes were simultaneously present in specific granules of the intestinal eosinophils. Quantitative analysis of the labeling on subcellular compartments confirmed that all enzymes examined are significantly localized within specific granules and that there is no significant labeling on other compartments such as the nucleus and cytoplasm. In the control sections incubated with an immunoglobulin G fraction from nonimmunized rabbits, no specific labeling was seen on the granules or other organelles. These findings indicate that enzymes which previously have been identified in some organs as lysosomal and in others as peroxisomal can be found together in eosinophil granules.
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PMID:Localization of lysosomal and peroxisomal enzymes in the specific granules of rat intestinal eosinophil leukocytes revealed by immunoelectron microscopic techniques. 669 57

The first step of peroxisomal fatty acid beta-oxidation is catalyzed by a family of acyl-CoA oxidase isozymes with distinct fatty acyl-CoA chain-length specificities. Here we identify a new acyl-CoA oxidase gene from Arabidopsis (AtACX3) following the isolation of a promoter-trapped mutant in which beta-glucuronidase expression was initially detected in the root meristem. In acx3 mutant seedlings medium-chain acyl-CoA oxidase activity was reduced by 95%, whereas long- and short-chain activities were unchanged. Despite this reduction in activity lipid catabolism and seedling development were not perturbed. AtACX3 was cloned and expressed in Escherichia coli. The recombinant enzyme displayed medium-chain acyl-CoA substrate specificity. Analysis of beta-glucuronidase activity in acx3 revealed that, in addition to constitutive expression in the root axis, AtACX3 is also up-regulated strongly in the hypocotyl and cotyledons of germinating seedlings. This suggests that beta-oxidation is regulated predominantly at the level of transcription in germinating oilseeds. After the discovery of AtACX3, the Arabidopsis acyl-CoA oxidase gene family now comprises four isozymes with substrate specificities that encompass the full range of acyl-CoA chain lengths that exist in vivo.
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PMID:Promoter trapping of a novel medium-chain acyl-CoA oxidase, which is induced transcriptionally during Arabidopsis seed germination. 1091 60

Plant peroxisomes contain at least four proteins, namely, citrate synthase, malate dehydrogenase, long-chain acyl-CoA oxidase, and 3-ketoacyl-CoA thiolase, which are synthesized as large precursors with an N-terminal cleavable presequence. Each presequence has a conserved domain (R[I/L/Q]-X5-HL) that is homologous to peroxisomal targeting signal 2 from mammals and yeasts. In addition, a cysteine residue is found at the C-terminal ends of the presequences, whose function has not yet been described. The authors analyzed the function of the presequences and the conserved amino acids using transgenic Arabidopsis plants, which accumulate beta-glucuronidase carrying the presequence of the peroxisomal proteins from plants. Immunological and immunocytochemical studies on the transgenic plants showed that a conserved sequence in the extrapeptides is essential for targeting to peroxisomes, and a cysteine residue at the cleavage site is involved in the processing of the presequence. These results suggest that the presequences of the peroxisomal proteins function as targeting signals, and are necessary for the recognition of the processing.
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PMID:Transport of peroxisomal proteins synthesized as large precursors in plants. 1133 56