TRNA (pseudouridine<sup>54</sup>-N<sup>1</sup>)-methyltransferase (, TrmY, m1Psi methyltransferase) is an enzyme with systematic name S-adenosyl-L-methionine:tRNA (pseudouridine54-N1)-methyltransferase. This enzyme catalyses the following chemical reaction
This archaeal enzyme is specific for the 54 position.