PRMT3, as known as protein arginine N-methyltransferase 3, belongs to the protein arginine methyltransferase family. This enzyme catalyzes the methylation of guanidino nitrogens of arginyl residues of proteins. It acts on 40S ribosomal protein S2 (rpS2), which is its major in-vivo substrate, and is involved in the proper maturation of the 80S ribosome. Recombinant human PRMT3, fused to His-tag at N-terminus, was expressed in E.coli and purified by using conventional chromatography techniques.