Purification and Characterization of Isocitrate Lyase from Ethanol-grown Euglena gracilis |
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| Authors: | KOUKI ONO MASAHIRO OKIHASHI HIROSHI INUI KAZUTAKA MIYATAKE SHOZABURO KITAOKA YOSHIHISA NAKANO |
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| Institution: | Department of Applied Biological Chemistry, University of Osaka Prefecture, Sakai, Osaka 593, Japan.;Department of Agricultural Biochemistry and Biotechnology, Tottori University, Tottori 680, Japan |
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| Abstract: | Isocitrate lyase was purified to homogeneity from ethanol-grown Euglena gracilis. The specific activity was 0.26 μmol/min/mg protein. The molecular mass of the enzyme was calculated to be 380 kDa by gel filtration on a Superose 6 column. The subunit molecular mass of the enzyme was 116 kDa as determined by SDS-polyacrylamide gel electrophoresis. These results showed that the native form of this enzyme was a trimer composed of three identical subunits. The pH optimum for cleavage and condensation reactions was 6.5 and 7.0, respectively. The Km values for isocitrate, glyoxylate and succinate were 3.8, 1.3 and 7.7 mM, respectively. Isocitrate lyase absolutely required Mg for enzymatic activity. This is the first report of the purification of isocitrate lyase to homogeneity from Euglena gracilis. |
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| Keywords: | Alcohol metabolism gluconeogenesis glyoxylate cycle glyoxysome microbody |
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