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)

Homogenates of HTC cells have been fractionated by differential centrifugation (in four particulate fractions: N, M, L, P, and a supernatant S) or isopycnic banding in linear sucrose gradients. On this basis, the following subcellular organelles may be characterized: (i) Mitochondria, detected by cytochrome oxidase and succinodehydrogenase, are collected in the M and L fractions, and equilibrate, as a narrow band, at a median buoyant density of 1.18 g/cm3. (ii) Lysosomes, detected by the latent hydrolases beta-glycerophosphatase and N-acetyl-beta-glucosaminidase, are largely sedimented in the M and L fractions, and display a broad density distribution pattern with a median value of 1.17 g/cm3. This density is decreased or increased after cultivation of the cells in presence of Triton WR-1339 or Dextran 500, respectively. The behavior of cathepsin D is somewhat at variance with that of the two other hydrolases. (iii) Plasma membrane is tentatively detected by alkaline phosphodiesterase I. Largely recovered in the P fraction, this enzyme equilibrates at a median density close to that of the lysosomal hydrolases; the bulk of cholesterol and about half of the leucyl-2-naphthylamidase are closely associated with alkaline phosphodiesterase I; HTC cells do not contain typical 5'-nucleotidase. (iv) Catalase-bearing particles, of high buoyant density (1.22 g/cm3) are present, but 30-40% of the catalase is also found readily soluble. NADPH- and NADH: cytochrome c reductase, and RNA show more complex distributions. It is suggested that the former enzyme is associated with the endoplasmic reticulum; as in liver, NADH reductase activity is shared between the endoplasmic reticulum and the mitochondria; half of the RNA is associated with free ribosomes of polysomes. True glucose-6-phosphatase could not be detected.
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PMID:Analytical fractionation of cultured hepatoma cells (HTC cells). 56 43

A purification scheme is described for the glyoxylate cycle enzyme malate synthase from maize scutella. With our procedure, large amounts of extremely pure enzyme can easily be prepared. Purification involves a heat denaturation step, followed by ammonium sulfate precipitation, and chromatography on DEAE-cellulose and Blue Dextran-Sepharose. Catalase and malate dehydrogenase, which are the most persistent contaminants, are completely removed by this procedure. Maize malate synthase is an octameric protein with a subunit molecular weight of 64 kDa. Purity of the enzyme preparation was demonstrated by SDS-polyacrylamide gel electrophoresis and by isoelectric focusing (pI = 5.0). Pure malate synthase can be stored without appreciable loss of activity at -70 degrees C in 200 mM Hepes buffer containing 6 mM MgCl2 and 2 mM 2-mercaptoethanol, pH 7.6. Maize malate synthase contains no covalently linked carbohydrate residues. The enzyme requires Mg2+ ions for activity. From circular dichroism measurements we estimate that the secondary structure of the enzyme consists of 30% alpha-helical and almost no (5%) beta-pleated sheet segments. A 45-kDa polypeptide, which contaminates malate synthase preparations if the purification starts from seedlings older than 2.5 days, is shown to be a degradation product of malate synthase. Together with full-length chains, these 45-kDa polypeptides are able to take part in octameric oligomer formation.
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PMID:Purification of the glyoxylate cycle enzyme malate synthase from maize (Zea mays L.) and characterization of a proteolytic fragment. 828 48