Gene/Protein Disease Symptom Drug Enzyme Compound
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Query: UNIPROT:P04040 (Catalase)
 3,577 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

We established a Chinese hamster ovary cell line having a temperature-sensitive phenotype in peroxisome biogenesis. This mutant (65TS) was produced by transforming a PEX2-defective mutant, Z65, with a mutant PEX2 gene, PEX2(E55K), derived from a patient with infantile Refsum disease, a milder form of peroxisome biogenesis disorder. In 65TS, catalase was found in the cytosol at a nonpermissive temperature (39 degrees C), but upon the shift to a permissive temperature (33 degrees C), catalase gradually localized to the structures containing a 70-kDa peroxisomal membrane protein, PMP70. In contrast to catalase, other matrix proteins containing typical peroxisome targeting signals, acyl-CoA oxidase and peroxisomal 3-ketoacyl-CoA thiolase, were co-localized with PMP70 in most cells, even at 39 degrees C. We found that these structures are partially functional peroxisomes and named them "catalase-less peroxisomes." Catalase-less peroxisomes were also observed in human fibroblasts from patients with milder forms of peroxisome biogenesis disorder, including the one from which the mutant PEX2 gene was derived. We suggest that these structures are the causes of the milder phenotypes of the patients. Temperature-dependent restoration of the peroxisomes in 65TS occurred even in the presence of cycloheximide, a protein synthesis inhibitor. Thus, we conclude that in 65TS, catalase-less peroxisomes are the direct precursors of peroxisomes.
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PMID:Catalase-less peroxisomes. Implication in the milder forms of peroxisome biogenesis disorder. 1096 Apr 80

Catalase activity, a peroxisomal marker enzyme, was not detectable in any of the subcellular fractions of Spodoptera frugiperda (Sf) 21 insect cells, although marker enzymes in other organelles were distributed in the fractions in a manner similar to that seen in mammalian cells. When a green fluorescent protein fused with peroxisome targeting signal 1 at the C-terminal (GFP-SKL) was expressed in Sf21 cells, punctate fluorescent dots were observed in the cytoplasm. The fraction where GFP-SKL was concentrated exhibited long-chain and very-long-chain fatty acid beta-oxidation activities in the presence of KCN and the density of this fraction was slightly higher than that of mitochondria. Immunoelectron microscopy studies with anti-SKL antibody demonstrated that Sf21 cells have immunoreactive peroxisome-like organelles which are structurally distinct from mitochondria, endoplasmic reticulum, and lysosomes. In contrast to peroxisomal matrix proteins, adrenoleukodystrophy protein, a peroxisomal membrane protein, was not located to peroxisomes. This suggests that the targeting signal for PMP in insect cells is distinct from that in mammalian cells. These results demonstrate that Sf21 insect cells have unique catalase-less peroxisomes capable of beta-oxidation of fatty acids.
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PMID:Existence of catalase-less peroxisomes in Sf21 insect cells. 1278 84