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'Enzyme Purification' in keywords Facet   section ZfN Section C  [X]
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1Author    Remigius Manderscheid, Aloysius WildRequires cookie*
 Title    Characterization of Glutamine Synthetase of Roots, Etiolated Cotyledons and Green Leaves from Sinapis alba (L.)  
 Abstract    Glutamine synthetase of roots, etiolated cotyledons and green leaves from mustard plants cannot all clearly be separated by DEAE-Sephacel chromatography. However, the enzyme of the roots, etiolated cotyledons and green leaves, respectively, differed in the kinetic properties deter­ mined in the crude extract. The root enzyme showed a pH-optimum of about 6.9, a K m value of 3 m M for glutamate and a temperature optimum at 48 °C. Glutamine synthetase of etiolated cotyledons possessed a Km for glutamate of 6 or 12 m M , depending on the dithioerythritol con­ centration in the homogenisation buffer and a temperature optimum at 46 °C. The enzyme of green leaves was characterized by a temperature optimum at 40 °C, a pH-optimum at about 7.4 and a low glutamate affinity with positive cooperative substrate binding. Based on isolation of chloroplasts and identification of glutamine synthetase the enzyme of green leaves seems to be the chloroplastic form. This enzyme was purified by DEAE-Sephacel, hydroxylapatite and Sephacryl S-300 chromatography. Affinity for glutamate and M g S04 of the purified enzyme differed from that found in the crude extract. The function of the different isoenzymes is discussed. Intro du ction 
  Reference    Z. Naturforsch. 41c, 712 (1986); received March 17 1986 
  Published    1986 
  Keywords    Enzyme Purification, Glutamine Synthetase, Isoenzymes, Photorespiration, Sinapis alba 
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 TEI-XML for    default:Reihe_C/41/ZNC-1986-41c-0712.pdf 
 Identifier    ZNC-1986-41c-0712 
 Volume    41 
2Author    Joseph Veser, P. Eter, G.Requires cookie*
 Title    Purification and Properties of a Catechol Methyltransferase of the Yeast Candida tropicalis  
 Abstract    In an effort to investigate catechol methyltransferase activity in sources other than mam m alian tissues and cells, a high level o f enzyme activity was found in the yeast fungus Candida tropicalis CBS 94. Partial purification o f the enzyme (approx. 550 fold with a recovery o f 7%) could be achieved by using ion-exchange and gel filtration techniques. The molecular w eight was estimated at 32,000 ± 2,000 by gel filtration on Sephadex G-100. In isoelectric focusing experiments on Sephadex G-75 the enzym e exhibited a pl-value o f 5.0 ± 0.1. In contrast to catechol methyltransfer­ ase from various m am m alian tissues the enzyme activity was prepared from the pH 5-sediment. The substrate specifity is com parable to other catechol methyltransferases. 
  Reference    Z. Naturforsch. 34c, 709 (1979); received April 24 1979 
  Published    1979 
  Keywords    Catechol Methyltransferase, Yeast Fungus, Candida tropicalis CBS 94, Enzyme Purification, Catechols 
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 TEI-XML for    default:Reihe_C/34/ZNC-1979-34c-0709.pdf 
 Identifier    ZNC-1979-34c-0709 
 Volume    34 
3Author    Matthias Höpfner, Georg Reifferscheid, Aloysius WildRequires cookie*
 Title    Molecular Composition of Glutamine Synthetase of Sinapis alba L  
 Abstract    Chloroplastic glutamine synthetase of Sinapis alba, purified to homogeneity by a simple three step procedure, revealed a molecular weight of about 395 kDa. The native enzyme is composed of eight subunits of identical molecular weight (about 50 kDa (each), although isoelectrofocusing yielded six distinct bands in the pH 5.6 region of the gel. Labelling of the enzyme with the glutamate analogue herbicide [ 14 C]phosphinothricin and with [y-32 P]ATP indicated that glutamine synthetase has eight reactive centers per molecule. The native enzyme dissociated into two enzymatically active subaggregates of about 195 kDa after Mg 2+ deprivation. 
  Reference    Z. Naturforsch. 43c, 194—198 (1988); received November 26 1987 
  Published    1988 
  Keywords    Active Centers, Enzyme Purification, Enzyme Structure, Glufosinate, Glutamine Synthetase, Phosphinothricin 
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 TEI-XML for    default:Reihe_C/43/ZNC-1988-43c-0194.pdf 
 Identifier    ZNC-1988-43c-0194 
 Volume    43 
4Author    M. Aria, C. Alvarez-Ossorioa, FranciscoJ G M Uriana3, FranciscoF. De La Rosab, AngelM. RelimpioaRequires cookie*
 Title    Purification and Characterization of Nitrate Reductase from the Halophile Archaebacterium Haloferax mediterranei  
 Abstract    Nitrate reductase is induced in cells o f H aloferax mediterranei by the presence o f nitrate upon anaerobic conditions. This enzyme was purified more than 35-fold with a yield o f 49%. Densitograms o f polyacrylamide gel electrophoresis show the preparation to be 85% purity. The best enzyme preparation has a specific activity o f 13.6 U /m g protein. It is the first halo­ philic nitrate reductase that has been purified near to homogeneity. The purification consists o f five steps: an amm onium sulphate precipitation and four successive gel chromatographies with Sepharose C L -4B, calcium phosphate, D EAE-Sephacel and Sephacryl S-200. An average Mr o f 170,000 was estimated by gel chromatography and non-denaturing gel electrophoresis. Effectiveness o f electron donors, cofactors and inhibitors are reported. At low salt concentra­ tion the halophilic nitrate reductase was inactivated follow ing first-order kinetics. The K m for nitrate depends on salt concentration and shows values in the range from 2.5 to 6.7 m M . 
  Reference    Z. Naturforsch. 47c, 670—6 (1992); received April 7/June 15 1992 
  Published    1992 
  Keywords    Halophilic Nitrate Reductase, Enzyme Purification, Enzyme Characterization, Haloferax mediterranei 
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 TEI-XML for    default:Reihe_C/47/ZNC-1992-47c-0670.pdf 
 Identifier    ZNC-1992-47c-0670 
 Volume    47 
5Author    Manfred GrieshaberRequires cookie*
  Reference    Z. Naturforsch. 33c, 235 (1978); received December 30 1977/February 21 1978 
  Published    1978 
  Keywords    Oligocephalic Enzymes, Enzyme Purification, Glutamine-Chorismate-Amidotransferase-Free Anthranilate Phosphoribosyltransferases, Subunit Assembly, Enzyme Evolution 
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 TEI-XML for    default:Reihe_C/33/ZNC-1978-33c-0235.pdf 
 Identifier    ZNC-1978-33c-0235 
 Volume    33 
6Author    Thomas Weber3, ThomasJ. BachbRequires cookie*
 Title    Partial Purification and Characterization of Membrane-Associated 3-Hydroxy-3-methylglutaryl-Coenzyme A Lyase from Radish Seedlings  
 Abstract    We solubilized from radish membranes and purified by 154-fold 3-hydroxy-3-methyl-glutaryl-CoA lyase (H M G L, EC catalyzing the conversion o f 3-hydroxy-3-methyl-glutaryl-(H M G -)C oA into acetyl-CoA and acetoacetate. The apparent molecular mass under non-denaturating conditions is 70 kDa. The enzyme has a broad pH optimum around 8.0 and its activation energy as determined from the linear part o f an Arrhenius plot is 137.1 kJ/mol. The K m with respect to (5)-H M G -C oA is 40 |iM . The enzyme is extremely unstable and rapidly loses activity even when kept on ice, but retains some activity over several weeks when stored at -8 0 °C. 
  Reference    Z. Naturforsch. 48c, 444 (1993); received March 12/April 13 1993 
  Published    1993 
  Keywords    Radish, Enzyme Purification, M evalonate Shunt, Leucine D egradation, H M G -C oA Synthesis, H M G -C oA M etabolism 
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 TEI-XML for    default:Reihe_C/48/ZNC-1993-48c-0444.pdf 
 Identifier    ZNC-1993-48c-0444 
 Volume    48