Active Site

Pyridine nucleotide-disulphide oxidoreductase, class I, active site (IPR012999)

Short name: Pyr_OxRdtase_I_AS


The pyridine nucleotide-disulphide oxidoreductases are FAD flavoproteins which contain 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 [PMID: 2067578] these enzymes can be classified into two categories. The first category groups together the following enzymes [PMID: 6546954, PMID: 2643922, PMID: 1957352, PMID: 7589432]:

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

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

Note: 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 [PMID: 1303792].

GO terms

Biological Process

GO:0055114 oxidation-reduction process

Molecular Function

GO:0016668 oxidoreductase activity, acting on a sulfur group of donors, NAD(P) as acceptor

Cellular Component

No terms assigned in this category.

Contributing signatures

Signatures from InterPro member databases are used to construct an entry.
PROSITE patterns