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Arginyl-tRNA Synthetase from Mycobacterium smegmatis SN2: Purification and Kinetic Mechanism

Char, Shobha and Gopinathan, Karumathil P (1986) Arginyl-tRNA Synthetase from Mycobacterium smegmatis SN2: Purification and Kinetic Mechanism. In: The Journal of Biochemistry, 100 (2). pp. 349-357.

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Abstract

Arginyl-tRNA synthetase $[L-Arg: tRNA^{Arg})$ ligase (AMP forming) EC 6.1.1.19 [EC]] has been purified to homogeneity from Mycobacterium smegmatis SN2. The enzyme is a monomer of molecular weight 56,000. The kinetic patterns obtained by initial velocity and product inhibition studies are consistent with a rapid equilibrium random ter-ter mechanism. Polyamines stimulated the formation of arginyl-tRNA, the stimulation being more significant at sub-optimal $Mg^{2+}$ concentrations. Initial velocity studies performed in the presence of sub-optimal $Mg^{2+}$ and spermine also indicated that the kinetic mechanism remained sequential random. Various attempts to reveal the formation of enzyme-bound arginyl-adenylate provided no evidence for its existence. The reverse reaction, i.e the deacylation of arginyl-tRNA, required both AMP and $PP_1$. This observation is consistent with the mechanism proposed.

Item Type: Journal Article
Additional Information: Copyright of this article belongs to Japanese Biochemical Society.
Department/Centre: Division of Biological Sciences > Microbiology & Cell Biology
Date Deposited: 15 Jul 2008
Last Modified: 27 Aug 2008 13:31
URI: http://eprints.iisc.ernet.in/id/eprint/14680

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