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Query: UNIPROT:P04040 (Catalase)
 3,577 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

A purification scheme is described for the glyoxylate cycle enzyme isocitrate lyase from maize scutella. Purification involves an acetone precipitation and a heat denaturation step, followed by ammonium sulfate precipitation and chromatography on DEAE-cellulose and on blue-Sepharose. The latter step results in the removal of the remaining malate dehydrogenase activity, and of a high molecular mass (62 kDa) but inactive degradation product of isocitrate lyase. Catalase can be completely removed by performing the DEAE-cellulose chromatography in the presence of Triton X-100. Pure isocitrate lyase can be stored without appreciable loss of activity at -70 degrees C in 5 mM triethanolamine buffer containing 6 mM MgCl2, 7 mM 2-mercaptoethanol, and 50% (v/v) glycerol, pH 7.6. Maize isocitrate lyase is a tetrameric protein with a subunit molecular mass of 64 kDa. Purity of the enzyme preparation was demonstrated by polyacrylamide gel electrophoresis in the presence of dodecylsulfate, in acid (pH 3.2) urea and by isoelectric focusing (pI = 5.1). Maize isocitrate lyase is devoid of covalently linked sugar residues. From circular dichroism measurements we estimate that its structure comprises 30% alpha-helical and 15% beta-pleated sheet segments. The enzyme requires Mg2+ ions for activity, and only Mn2+ apparently is able to replace this cation to a certain extent. The kinetics of the isocitrate lyase-catalyzed cleavage reaction were investigated, and the amino acid composition of the maize enzyme was determined. Finally the occurrence of an association between maize isocitrate lyase and catalase was observed. Such a multienzyme complex may be postulated to play a protective role in vivo.
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PMID:The purification and physicochemical characterization of maize (Zea mays L.) isocitrate lyase. 163 86

Catalase (EC 1.11.1.6) was purified to near homogeneity from isolated megagametophytes of germinated loblolly pine (Pinus taeda L.) seeds, and monospecific antibodies were elicited in rabbits. Following a procedure that involved acetone extraction, (NH4)2SO4 fractionation, and four chromatographic steps (i.e. DE-52 cellulose, Superdex-200, hydroxylapatite, and phenyl-Sepharose CL-4B), catalase was purified about 140-fold to a final specific activity of 2215 mmol min-1 mg-1 of protein. Cotton isocitrate lyase antibodies were used, and protein immunoblots revealed that the resolution on hydroxylapatite and phenyl-Sepharose allowed for the complete separation of catalase from contaminating isocitrate lyase. The molecular masses of the native enzyme and its subunit are 235 and 59 kD, respectively, indicating that the pine holoenzyme is a homotetramer. Loblolly pine catalase exists as multiple isoforms. When megagametophytes taken 7 d after imbibition at 30[deg]C were extracted, subjected to nondenaturing isoelectric focusing, and stained for catalase activity, at least four catalase isoforms were observed, including one dominant form with an isoelectric point of 6.87. Purified pine catalase is not a glycoprotein and has a ratio of absorbance at 208 nm to absorbance at 405 nm of 1.5. When probed with loblolly pine catalase antibodies, protein blots of cell-free extracts from megagametophytes of mature, stratified, and germinated loblolly pine seeds, the megagametophyte glyoxysomal fraction, and purified loblolly pine catalase all revealed one immunoreactive 59-kD polypeptide. This indicates that no detectable change in the enzyme's monomeric molecular mass occurs during seed stratification and germination, early seedling growth, and purification.
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PMID:Purification and Characterization of Catalase from Loblolly Pine (Pinus taeda L.) Megagametophytes. 1223 55

Changes in the ultrastructural aspect of the glyoxysome fraction obtained from maize scutella by density gradient centrifugation were followed during the first 6 days of germination. During the first 2 days the fraction consists of very electron-dense bodies about 0.3 to 0.5 micron in size while at the 4th day it is formed by larger and less dense membrane-bound particles. Some intermediate form between the two types of organelles can be seen at the 3rd day. Between the 4th and the 6th days of germination the glyoxysomes are destroyed, and their enzymes are released into the cytosol. At the peak of their development (4th day) the glyoxysomes contain 75 to 80% of the total isocitratase and 65% of the total malate synthetase of the scutellum. These values drop to very low levels during the next 2 days. Catalase bound to glyoxysomes amounts to 30 to 35% of the total activity present in the scutellum at the 1st day of germination: this value decreases steadily during the following days.
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PMID:The development of glyoxysomes in maize scutellum: changes in morphology and enzyme compartmentation. 1665 12

The sequence of glyoxysomal enzyme development was investigated in cotyledons of cotton (Gossypium hirsutum L. cv. Deltapine 16) embryos from 16 to 70 days after anthesis (DAA). Catalase, malate dehydrogenase, and citrate condensing enzyme activities were barely detectable prior to 22 DAA, but showed dramatic increases from 22 to 50 DAA. Development of malate synthase activity, however, was delayed during this period, rising to peak activity from 45 to 50 DAA (just prior to desiccation) in the absence of any detectable isocitrate lyase activity. Substantial activities of all of these enzymes (except isocitrate lyase) persisted in the dry seeds. Isopycnic centrifugations on sucrose gradients demonstrated that the enzymes were compartmentalized within particles increasing in buoyant density with time of development (1.226 to 1.245 grams per cubic centimeter from 22 to 50 DAA). Of particular significance were the observations in 22-day embryos of smooth surfaced membrane dilations of rough endoplasmic reticulum having cytochemical catalase reactivity, and the demonstrations of catalase activities in microsomal fractions isolated throughout the 16- to 50-DAA period. Our data do not allow determination of the mechanism(s) for enzyme activation and/or addition to previously existing or newly formed microbodies, but do show that development and acquisition of enzyme activities within glyoxysomes occur sequentially and thus are not regulated in concert as previously thought.
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PMID:Control of Enzyme Activities in Cotton Cotyledons during Maturation and Germination: II. Glyoxysomal Enzyme Development in Embryos. 1666 Apr 55

The distribution of glyoxylate-cycle enzymes between microbodies and mitochondria was examined in ethanol-grown Aspergillus tamarii Kita. Particulate activities of catalase and the two glyoxylate by-pass enzymes, malate synthase and isocitrate lyase, were localized in the microbodies. The microbodies had a buoyant density of about 1.23 g cm(-3) after isopycnic centrifugation in linear sucrose gradients. Particulate activities of the other two glyoxycitrate synthase, together with that of succinate dehydrogenase were restricted to the mitochondria, which had a buoyant density of about 1.20 g cm(-3). Catalase also appeared to be localized in a second particle, perhaps the microbody inclusions or the Woronin bodies, having a buoyant density of about 1.26 g cm(-3).
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PMID:Distribution of glyoxylate-cycle enzymes between microbodies and mitochondria in Aspergillus tamarii. 2442 91

Microbodies were observed in the hyphal tips of all 14 fungi investigated. Their morphology varied among the fungi and their numbers were influenced by the growth medium. Microbodies were closely associated with mitochondria in one fungus and with the endoplasmic reticulum in several fungi. Catalase was not detected in microbodies with the diaminobenzidine cytochemical procedure even though catalase activity was present in extracts of these fungi. The activities of the glyoxylate-cycle enzymes isocitrate lyase and malate synthase were affected by the growth medium and were particulate in the two fungi studied by differential centrifugation. Microbodies are abundant, and they are ubiquitous among the fungi and in some cases they may contain glyoxylate-cycle enzymes.
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PMID:Microbodies and glyoxylate-cycle enzyme activities in filamentous fungi. 2443 28