23S rRNA (guanine<sup>748</sup>-N<sup>1</sup>)-methyltransferase (, Rlma(II), Rlma2, 23S rRNA m1G748 methyltransferase, RlmaII, Rlma II, tylosin-resistance methyltransferase RlmA(II), TlrB, rRNA large subunit methyltransferase II) is an enzyme with systematic name S-adenosyl-L-methionine:23S rRNA (guanine<sup>748</sup>-N<sup>1</sup>)-methyltransferase. This enzyme catalyses the following chemical reaction
The enzyme specifically methylates guanine<sup>748</sup> at N<sup>1</sup> in 23S rRNA.