Higher specific activity of the Escherichia coli glutamyl-tRNA synthetase purified to homogeneity by a six-hour procedure. |
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| Authors: | S X Lin A Brisson J Liu P H Roy J Lapointe |
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| Affiliation: | Département de biochimie, Faculté des sciences et de génie, Université Laval, Québec, Canada. |
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| Abstract: | The glutamyl-tRNA synthetase (EC 6.1.1.17) of Escherichia coli was purified to homogeneity from the overproducing strain DH5 alpha(pLQ7612) by a two-step procedure that takes only about 6 h and yields 10 mg of enzyme per gram of wet cells. The process consists of a two-phase polyethylene glycol-dextran partition, the top phase of which is diluted and directly applied to an anion-exchange FPLC MonoQ column. The purified enzyme has a specific activity about twice that of the same enzyme purified to homogeneity by the lengthy conventional procedure from either a normal strain or this overproducing strain. This difference is discussed in relation to the generation of microheterogeneity in proteins during their purification. |
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