Immunogen sequence: EGAWNKENRF CSWVDQKLNS EGMEEARNCG KQLKALNFEF DLVFTSVLNR SIHTAWLILE ELGQEWVPVE SSWRLNERHY GALIGLNREQ MALNHGEEQV. Riboflavin kinase is an essential enzyme that catalyzes the phosphorylation of riboflavin to form flavin mononucleotide, an