Flavin reductase

Function

Flavin reductase (FR) catalyzes the NADPH-dependent reduction of a variety of flavins such as riboflavin, FAD, FMN, biliverdin, methemoglobin and pyrroloquinoline quinone. FR converts reduced riboflavin to riboflavin and bilirubin to biliverdin. FR is involved in heme catabolism^[1] .

Relevance

FR catalytic reaction is the basis of the therapeutic use of methylene blue or riboflavin in the treatment of methemoglobinemia. Bacterial FR are used to sensitize tumors to drugs.

Structural insights

The NADP containing active site can accommodate a variety of ligands because the binding is achieved via mainly hydrophobic interactions.

Human flavin reductase complex with biliverdin IX α and NADP (PDB code 1he2)

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3D structures of flavin reductase3D structures of flavin reductase

Updated on 22-January-2016

1qfj – FR – Escherichia coli
1bkj – VhFR + FMN – Vibrio harveyi
2bkj - VhFR + NAD + FMN
1hdo - hFR + NADP - human
1he2 - hFR + biliverdin IX α + NADP
1he3 - hFR + mesobiliverdin IV α + NADP
1he4 - hFR + FMN + NADP
1he5 - hFR + lumichrome + NADP
1rz0 – GtFR + FAD – Geobacillus thermoglucosidasius
1rz1 - GtFR + FAD + NAD
3pft - FR (mutant) + FMN – Mycobacterium goodii

ReferencesReferences

↑ Yubisui T, Takeshita M, Yoneyama Y. Reduction of methemoglobin through flavin at the physiological concentration by NADPH-flavin reductase of human erythrocytes. J Biochem. 1980 Jun;87(6):1715-20. PMID:7400118

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Michal Harel, Alexander Berchansky, Joel L. Sussman

[1] Yubisui T, Takeshita M, Yoneyama Y. Reduction of methemoglobin through flavin at the physiological concentration by NADPH-flavin reductase of human erythrocytes. J Biochem. 1980 Jun;87(6):1715-20. PMID:7400118

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