23S rRNA (guanine<sup>2445</sup>-N<sup>2</sup>)-methyltransferase (, ycbY (gene), rlmL (gene)) is an enzyme with systematic name S-adenosyl-L-methionine:23S rRNA (guanine<sup>2445</sup>-N<sup>2</sup>)-methyltransferase. This enzyme catalyses the following chemical reaction
The enzyme methylates 23S rRNA in vitro.