Molecular Composition of Glutamine Synthetase of Sinapis alba L
نویسنده
چکیده
Matthias Höpfner , Georg Reifferscheid, and Aloysius Wild Institut für Allgemeine Botanik der Johannes Gutenberg-Universität, Saarstraße 21, D-6500 Mainz, Bundesrepublik Deutschland Z. Naturforsch. 43c, 194-198 (1988); received November 26, 1987 Active Centers, Enzyme Purification, Enzyme Structure, Glufosinate, Glutamine Synthetase, Phosphinothricin 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 [C]phosphinothricin and with [y-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 deprivation.
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