PRMT5/MEP50 complex of human PRMT5 (GenBank Accession No. NM_006109), amino-acids 2-637(end), with N-terminal FLAG-Avi tag, MW=73 kDa, and human MEP50 (GenBank Accession No. NM_024102) with N-terminal His-Tag, amino-acids 2-342(end), MW=38 kDa, coexpressed in HEK293 cells and enzymatically biotin-labeled using Avi-tag™ technology.