EC - NADPH—hemoprotein reductase

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IntEnz Enzyme Nomenclature


Accepted name:
NADPH—hemoprotein reductase
Other names:
FAD-cytochrome c reductase
NADP—cytochrome c reductase
NADP—cytochrome reductase
NADPH-dependent cytochrome c reductase
NADPH:P-450 reductase
NADPH:ferrihemoprotein oxidoreductase
NADPH—cytochrome P-450 oxidoreductase
NADPH—cytochrome c oxidoreductase
NADPH—cytochrome c reductase
NADPH—cytochrome p-450 reductase
NADPH—ferricytochrome c oxidoreductase
NADPH—ferrihemoprotein reductase
TPNH2 cytochrome c reductase
TPNH-cytochrome c reductase
aldehyde reductase (NADPH-dependent)
cytochrome P-450 reductase
cytochrome c reductase (reduced nicotinamide adenine dinucleotide phosphate, NADPH, NADPH-dependent)
dihydroxynicotinamide adenine dinucleotide phosphate-cytochrome c reductase
ferrihemoprotein P-450 reductase
reduced nicotinamide adenine dinucleotide phosphate-cytochrome c reductase
reductase, cytochrome c (reduced nicotinamide adenine dinucleotide phosphate)
cytochrome P450 reductase
NADPH—cytochrome P450 reductase
NADPH—cytochrome P450 oxidoreductase
NADPH:P450 reductase
Systematic name:
NADPH:hemoprotein oxidoreductase




A flavoprotein containing both FMN and FAD. This enzyme catalyses the transfer of electrons from NADPH, an obligatory two-electron donor, to microsomal P450 monooxygenases (e.g. EC, unspecific monooxygenase) by stabilizing the one-electron reduced form of the flavin cofactors FAD and FMN. It also reduces cytochrome b5 and cytochrome c. The number n in the equation is 1 if the hemoprotein undergoes a 2-electron reduction, and is 2 if it undergoes a 1-electron reduction.

Links to other databases

Enzymes and pathways: NC-IUBMB , BRENDA , ExplorEnz , ENZYME@ExPASy , KEGG , MetaCyc , UniPathway
Structural data: CSA , EC2PDB
Gene Ontology: GO:0003958
CAS Registry Number: 9023-03-4
UniProtKB/Swiss-Prot: (41) [show] [UniProt]


  1. Haas, E., Horecker, B.L. and Hogness, T.R.
    The enzymatic reduction of cytochrome c, cytochrome c reductase.
    J. Biol. Chem. 136 : 747-774 (1940).
  2. Horecker, B.L.
    Triphosphopyridine nucleotide-cytochrome c reductase in liver.
    J. Biol. Chem. 183 : 593-605 (1950).
  3. Lu, A.Y.H., Junk, K.W. and Coon, M.J.
    Resolution of the cytochrome P-450-containing ω-hydroxylation system of liver microsomes into three components.
    J. Biol. Chem. 244 : 3714-3721 (1969). [PMID: 4389465]
  4. Masters, B.S.S., Kamin, H., Gibson, Q.H. and Williams, C.H., Jr.
    Studies on the mechanism of microsomal triphosphopyridine nucleotide-cytochrome c reductase.
    J. Biol. Chem. 240 : 921-931 (1965).
  5. Williams, C.H.,Jr. and Kamin, H.
    Microsomal triphosphopyridine nucleotide-cytochrome c reductase in liver.
    J. Biol. Chem. 237 : 587-595 (1962). [PMID: 14007123]
  6. Masters, B.S.S., Bilimoria, M.H, Kamen, H. and Gibson, Q.H.
    The mechanism of 1- and 2-electron transfers catalyzed by reduced triphosphopyridine nucleotide-cytochrome c reductase.
    J. Biol. Chem. 240 : 4081-4088 (1965). [PMID: 4378860]
  7. Sevrioukova, I.F. and Peterson, J.A.
    NADPH-P-450 reductase: Structural and functional comparisons of the eukaryotic and prokaryotic isoforms.
    Biochimie 77 : 562-572 (1995). [PMID: 8589067]
  8. Wang, M., Roberts, D.L., Paschke, R., Shea, T.M., Masters, B.S.S. and Kim, J.-J.P.
    Three-dimensional structure of NADPH-cytochrome P450 reductase: Prototype for FMN- and FAD-containing enzymes.
    Proc. Natl. Acad. Sci. USA 94 : 8411-8416 (1997). [PMID: 9237990]
  9. Munro, A.W., Noble, M.A., Robledo, L., Daff, S.N. and Chapman, S.K.
    Determination of the redox properties of human NADPH-cytochrome P450 reductase.
    Biochemistry 40 : 1956-1963 (2001). [PMID: 11329262]
  10. Gutierrez, A., Grunau, A., Paine, M., Munro, A.W., Wolf, C.R., Roberts, G.C.K. and Scrutton, N.S.
    Electron transfer in human cytochrome P450 reductase.
    Biochem. Soc. Trans. 31 : 497-501 (2003). [PMID: 12773143]

[EC created 1972, modified 2003]