... compilation ª 2008 FEBS 231 The occurrence of riboflavin kinase and FAD synthetase ensures FAD synthesis in tobacco mitochondria and maintenance of cellular redox status Teresa A. Giancaspero1, ... efficiencies.Once inside mitochondria, riboflavin is converted into catalytically activecofactors, FMN and FAD, due to the existence of a mitochondrial ribofla-vin kinase (EC 2.7.1.26) and an FAD synthetase ... functionality of mitochondrial electron transport, photosynthesis,metabolism of fatty acids, some amino acids, choline and betaine, and synthesis of vitamin B6, vitamin B12,folate, and protoporphyrin....