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)

The effects of the hepatic peroxisome proliferators (HPPs) clofibrate, di-(2-ethylhexyl)-phthalate (DEHP), mono-(2-ethylhexyl)phthalate (MEHP) and 2,4-dichlorophenoxy acetic acid (2,4-D) on the activities of some peroxisome-associated enzymes and marker enzymes for other organelles, have been studied in primary Syrian hamster embryo (SHE) cells and Wistar rat embryo (WRE) cells. The majority of the cells are fibroblast-like. 12-O-Tetradecanoyl phorbol-13-acetate (TPA) was included as it has been suggested that it may act as a peroxisome proliferator. The specific activities of catalase, fatty acyl-CoA oxidase (FAO) and peroxisomal beta-oxidation were approximately 100-fold lower in the embryonic cells than in rat hepatocytes. Other peroxisome-associated oxidases were not detected. The dihydroxyacetone-phosphate acyltransferase (DHAPAT) activity was comparable to that in rat liver. Marker enzymes for other organelles had specific activities comparable to rat hepatocytes. Catalase was shown by digitonin titration to be contained in a peroxisome-like compartment in both SHE and WRE cells. Clofibrate, DEHP and MEHP increased the catalase activity, which might suggest peroxisome proliferation. However, the findings that FAO and peroxisomal beta-oxidation did not increase or only very slightly, argue against peroxisome proliferation. 2,4-D and TPA induced no or only a very slight increase in the catalase activity.
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PMID:Effects of hepatic peroxisome proliferators and 12-O-tetradecanoyl phorbol-13-acetate on catalase and other enzyme activities of embryonic cells in vitro. 230 65

Peroxisomes were isolated from rat liver by pelleting a light mitochondrial (L) fraction over a 30% (w/v) Metrizamide layer. Peroxisomes were recovered as a loose pellet from the bottom of the tube and the purity of the peroxisomal fraction was calculated to be about 90%. The characteristics of dihydroxyacetone-phosphate acyltransferase (DHAP-AT) in the light mitochondrial fraction and the purified peroxisomal fraction were compared. The behaviour of the enzyme in the two fractions was very similar, except for the effect of sodium fluoride, which stimulated the activity in the L fraction 5-10-fold and in the peroxisomal fraction only 1.6-fold. This difference could be explained by the action of fluoride-sensitive acid phosphatases present in the L fraction that dephosphorylate palmitoyl-coenzyme A, a substrate for DHAP-AT. The localizations of DHAP-AT and alkyldihydroxyacetone-phosphate synthase in the rat liver peroxisomal membrane were studied. It is shown that in intact peroxisomes, DHAP-AT and alkyl-DHAP synthase are resistant to proteolytic inactivation by trypsin, as is fatty acid beta-oxidation activity, which served as a marker for the intactness of the peroxisomal membrane. Catalase was found not to be a suitable marker to assess peroxisome intactness in view of its relative insensitivity to trypsin. In 1-lauroyllysophosphatidylcholine-permeabilized peroxisomes, DHAP-AT, alkyl-DHAP synthase and beta-oxidation activities were rapidly inactivated by trypsin. It is concluded that in rat liver peroxisomes, at least the active sites of the integral membrane proteins DHAP-AT and alkyl-DHAP synthase are localized exclusively at the inner surface of the peroxisomal membrane.
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PMID:Rat liver dihydroxyacetone-phosphate acyltransferase: enzyme characteristics and localization studies. 317 24