Riboflavin metabolism

Riboflavin, also known as vitamin B₂ is an important component of the cofactors FAD and FMN. These cofactors form part of flavoproteins and essential for many metabolic pathways including fatty acid metabolism, citrate cycle and electron transport chain. FAD is a crucial electron acceptor in addition to NAD⁺ and NADP⁺ in these pathways. The apicomplexans Plasmodium, Toxoplasma, Theileria and Babesia species do not possess the metabolic ability to synthesise riboflavin de novo and therefore the enzymes involved in synthesis of riboflavin from GTP and ribulose 5-phosphate are absent in both genomes. These species salvage riboflavin from host and generate FMN and FAD de novo as these possess the enzymes riboflavin kinase and FAD synthase.