Nicotinamide and Its Methyltransferase as Apparent Inhibitors of tRNA Methylase
1972 年 71 巻 4 号 p. 719-723
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1972 年 71 巻 4 号 p. 719-723
An inhibitor for tRNA methylase was isolated and crystallized from the high speed supernatant fraction of rat liver by Dowex-50 (H+) column chromatography, and was identified as nicotinamide. Another nondialyzable protein factor was, however, shown to be required for the demonstration of the inhibitory action of nicotinamide. This factor was tentatively identified as nicotinamide methyltransferase [EC 2. 1. 1. 1]. Kinetic analyses indicated that the inhibitory action of both factors on tRNA meth-ylase appeared to be attributed to the competition of tRNA and nicotinamide transmethylases for a common substrate, S-adenosylmethionine.
