Riboflavin kinase
Riboflavin kinase (EC 2.7.1.26) is an enzyme that catalyzes the chemical reaction The enzyme originally characterised from plants and yeast converts the B vitamin, riboflavin, to flavin mononucleotide (FMN) by transferring a phosphate group from the cofactor, adenosine triphosphate (ATP), which is converted to adenosine diphosphate (ADP). Riboflavin is converted into catalytically active cofactors (FAD and FMN) by the actions of riboflavin kinase, which converts it into FMN, and FAD synthetase (EC 2.7.7.2), which adenylates FMN to FAD. Eukaryotes usually have two separate enzymes, while most prokaryotes have a single bifunctional protein that can carry out both catalyses, although exceptions occur in both cases.