TRNA (guanine<sup>9</sup>-N<sup>1</sup>)-methyltransferase (, Trm10p, tRNA(m1G9/m1A9)-methyltransferase, tRNA(m1G9/m1A9)MTase, tRNA (guanine-N(1)-)-methyltransferase, tRNA m1G9-methyltransferase, tRNA m1G9 MTase) is an enzyme with systematic name S-adenosyl-L-methionine:tRNA (guanine<sup>9</sup>-N<sup>1</sup>)-methyltransferase. This enzyme catalyses the following chemical reaction
The enzyme from Saccharomyces cerevisiae specifically methylates guanine<sup>9</sup>.