Purification and Characterization of Cytosolic NADP Specific Isocitrate Dehydrogenase from Pisum sativum
Author(s) -
Weiting Ni,
Eugene F. Robertson,
Henry C. Reeves
Publication year - 1987
Publication title -
plant physiology
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 3.554
H-Index - 312
eISSN - 1532-2548
pISSN - 0032-0889
DOI - 10.1104/pp.83.4.785
Subject(s) - isocitrate dehydrogenase , pisum , isoelectric focusing , biochemistry , sativum , enzyme , affinity chromatography , dehydrogenase , idh1 , chromatography , size exclusion chromatography , fractionation , isoelectric point , enzyme assay , cytosol , biology , chemistry , botany , gene , mutation
Cytosolic NADP-specific isocitrate dehydrogenase was isolated from leaves of Pisum sativum. The purified enzyme was obtained by ammonium sulfate fractionation, ion exchange, affinity, and gel filtration chromatography. The purification procedure yields greater than 50% of the total enzyme activity originally present in the crude extract. The enzyme has a native molecular weight of 90 kilodaltons and is resolved into two catalytically active bands by isoelectric focusing. Purified NADP-isocitrate dehydrogenase exhibited K(m) values of 23 micromolar for dl-isocitrate and 10 micromolar for NADP, and displayed optimum activity at pH 8.5 with both Mg(2+) and Mn(2+).
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