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PROPERTIES AND IMMUNOCHEMICAL CHARACTERIZATION OF NADPH‐SPECIFIC GLUTAMATEDEHYDROGENASE FROM EUGLENA GRACILIS
Author(s) -
JAVED QAMAR,
MERRETT MICHAEL J.
Publication year - 1986
Publication title -
new phytologist
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 3.742
H-Index - 244
eISSN - 1469-8137
pISSN - 0028-646X
DOI - 10.1111/j.1469-8137.1986.tb02908.x
Subject(s) - euglena gracilis , ouchterlony double immunodiffusion , molecular mass , euglena , biology , biochemistry , polyacrylamide gel electrophoresis , enzyme , glutamate dehydrogenase , microbiology and biotechnology , chemistry , antiserum , antigen , glutamate receptor , gene , genetics , receptor , chloroplast
S ummary The NADPH–glutamate dehydrogenase (GDH; EC 1.4.1.4) from glutamate–grown cells of Euglena gracilis Klebs strain z. Pringsheim was purified to homogeneity by the criterion of polyacrylamide gel electrophoresis. The holoenzyme was shown to have a relative molecular mass of 180000 and to be composed of four subunits with a relative molecular mass of 45000. The pH optimum for the animating reaction was 80. The Km values for NH 4 + , α‐oxoglutarate and NADPH were 0.4 mM, 1.4 mM and 0.18 mM, respectively. Antibodies raised to the purified enzyme showed no immunological correspondence with glutamic dehydrogenases from nitrate–grown Stichococus bacillaris and Porphyridium cruentum or ammonium–grown Chlorella vulgaris on Ouchterlony double–diffusion gels or by immuno–precipitation of enzyme activity. It is concluded that antigenic sites on the tetrameric Euglena enzyme may not be available on other NADPH–GDHs if they are hexamers.