Elementary plant Biochemistry and Biotechnology (2+1)

Riboflavin

• The flavin monoucleotide (FMN) and flavin adenine dinucleotide (FAD) are the two-coenzyme forms of riboflavin.
• FMN and FAD serve as prosthetic groups of oxidation-reduction enzymes known as flavoenzymes or flavoproteins.
• They are usually tightly, but not covalently, bound to the protein.
  
• Many flavoproteins contain one or more metals as additional cofactors and are known as the metalloflavoproteins.
  
• In the catalytic cycle of flavoproteins the flavin moiety of the flavin nucleotides undergoes reversible reduction of the isoalloxazine ring to yield the reduced nucleotides FMNH2 and FADH2.
• L-amino acid oxidase contains tightly bound FMN as the prosthetic group.
  
• Succinate dehydrogenase and D-amino acid oxidase contain FAD as prosthetic group.