TRNA (cytidine³²/uridine³²-2'-O)-methyltransferase (EC 2.1.1.200, YfhQ, tRNA:Cm³²/Um³² methyltransferase, TrMet(Xm³²), TrmJ) is an enzyme with systematic name S-adenosyl-L-methionine:tRNA (cytidine³²/uridine³²-2'-O)-methyltransferase.^[1] This enzyme catalyses the following chemical reaction

(1) S-adenosyl-L-methionine + cytidine³² in tRNA ${\displaystyle \rightleftharpoons }$ S-adenosyl-L-homocysteine + 2'-O-methylcytidine³² in tRNA

(2) S-adenosyl-L-methionine + uridine³² in tRNA ${\displaystyle \rightleftharpoons }$ S-adenosyl-L-homocysteine + 2'-O-methyluridine32 in tRNA

In Escherichia coli YfhQ is the only methyltransferase responsible for the formation of 2'-O-methylcytidine32 in tRNA.