TRNA (guanine<sup>26</sup>-N<sup>2</sup>)-dimethyltransferase (, Trm1p, TRM1, tRNA (m22G26)dimethyltransferase) is an enzyme with systematic name S-adenosyl-L-methionine:tRNA (guanine<sup>26</sup>-N<sup>2</sup>)-dimethyltransferase. This enzyme catalyses the following chemical reaction
The enzyme dissociates from its tRNA substrate between the two consecutive methylation reactions.