Riboflavin kinase, also known as flavokinase, belongs to the family of transferases, specifically those transferring phosphorus-containing groups (phosphotransferases) with an alcohol group as acceptor. It is an enzyme that catalyzes the phosphorylation of riboflavin (vitamin B2) to form flavin-mononucleotide (FMN). Recombinant riboflavin kinase was expressed in E.coli and purified by using conventional chromatography techniques.