PROSITE documentation PDOC00073

Pyridine nucleotide-disulphide oxidoreductases class-I active site


The pyridine nucleotide-disulphide oxidoreductases are FAD flavoproteins which contains a pair of redox-active cysteines involved in the transfer of reducing equivalents from the FAD cofactor to the substrate. On the basis of sequence and structural similarities [1] these enzymes can be classified into two categories. The first category groups together the following enzymes [2,3,4,5,6]:

  • Glutathione reductase (EC (GR).
  • Higher eukaryotes thioredoxin reductase (EC
  • Trypanothione reductase (EC
  • Lipoamide dehydrogenase (EC, the E3 component of α-ketoacid dehydrogenase complexes.
  • Mercuric reductase (EC

The sequence around the two cysteines involved in the redox-active disulfide bond is conserved and can be used as a signature pattern.


In positions 6 and 7 of the pattern all known sequences have Asn-(Val/ Ile) with the exception of GR from plant chloroplasts and from cyanobacteria which have Ile-Arg [7].

Last update:

May 2004 / Text revised.

Technical section

PROSITE method (with tools and information) covered by this documentation:

PYRIDINE_REDOX_1, PS00076; Pyridine nucleotide-disulphide oxidoreductases class-I active site  (PATTERN)


1AuthorsKurlyan J., Krishna T.S.R., Wong L., Guenther B., Pahler A., Williams C.H. Jr., Model P.
SourceNature 352:172-174(1991).

2AuthorsRice D.W., Schulz G.E., Guest J.R.
TitleStructural relationship between glutathione reductase and lipoamide dehydrogenase.
SourceJ. Mol. Biol. 174:483-496(1984).
PubMed ID6546954

3AuthorsBrown N.L.
SourceTrends Biochem. Sci. 10:400-402(1985).

4AuthorsCarothers D.J., Pons G., Patel M.S.
TitleDihydrolipoamide dehydrogenase: functional similarities and divergent evolution of the pyridine nucleotide-disulfide oxidoreductases.
SourceArch. Biochem. Biophys. 268:409-425(1989).
PubMed ID2643922

5AuthorsWalsh C.T., Bradley M., Nadeau K.
TitleMolecular studies on trypanothione reductase, a target for antiparasitic drugs.
SourceTrends Biochem. Sci. 16:305-309(1991).
PubMed ID1957352

6AuthorsGasdaska P.Y., Gasdaska J.R., Cochran S., Powis G.
TitleCloning and sequencing of a human thioredoxin reductase.
SourceFEBS Lett. 373:5-9(1995).
PubMed ID7589432

7AuthorsCreissen G., Edwards E.A., Enard C., Wellburn A., Mullineaux P.
TitleMolecular characterization of glutathione reductase cDNAs from pea (Pisum sativum L.).
SourcePlant J. 2:129-131(1992).
PubMed ID1303792

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