Purification and characterisation of glutamine synthetase fromNocardia corallina |
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Authors: | N. Illing R. T. Hill D. R. Woods |
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Affiliation: | (1) Department of Microbiology, University of Cape Town, 7700 Rondebosch, South Africa |
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Abstract: | Glutamine synthetase (GS) (EC 6.3.1.2) has been purified 67-fold fromNocardia corallina. The apparentMr of the GS subunit was approximately 56,000. Assuming the enzyme is a typical dodecamer this indicates a particle mass for the undissociated enzyme of 672,000. The GS is regulated by adenylylation and deadenylylation, and subject to feedback inhibition by alanine and glycine. The pH profiles assayed by the -glutamyl transferase method were similar for NH4+-treated and untreated cell extracts and an isoactivity point was not obtained from these curves. GS activity was repressed by (NH4)2SO4 and glutamate. Cells grown in the presence of glutamine, alanine, proline and histidine had enhanced levels of GS activity. The GS ofN. corallina cross-reacted with antisera prepared against GS from a Gram-negativeThiobacillus ferrooxidans strain but not with antisera raised against GS from a Gram-positiveClostridium acetobutylicum strain. |
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Keywords: | Nocardia corallina glutamine synthetase |
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