Nutritional biochemistry

A new redox-cofactor vitamin for mammals

Article metrics


Nicotinamides and flavins are essential cofactors in enzyme-catalysed reduction–oxidation (redox) reactions and are classified as vitamins because they must be supplied in the diet. Another redox cofactor, pyrroloquinoline quinone (PQQ), was first discovered in bacteria1 and is also likely to be important in mammals2,3, but the biochemical pathways in which it participates are unknown. Here we identify a PQQ-dependent dehydrogenase enzyme that is crucial for the degradation of the amino acid lysine in mice. PQQ is acting as a mammalian redox cofactor in this reaction, and therefore qualifies as a newcomer to the B group of vitamins.

Access options

Rent or Buy article

Get time limited or full article access on ReadCube.


All prices are NET prices.

Figure 1: The role of pyrroloquinoline quinone (PQQ) in mammalian lysine degradation.


  1. 1

    Salisbury, S. A., Forrest, H. S., Cruse, W. B. & Kennard, O. Nature 280, 843–844 (1979).

  2. 2

    Killgore, J. et al. Science 245, 850–852 (1989).

  3. 3

    Steinberg, F. M., Gershwin, M. E. & Rucker, R. B. J. Nutr. 124, 744–753 (1994).

  4. 4

    Higashino, K., Fujioka, M. & Yamamura, Y. Arch. Biochem. Biophys. 142, 606–614 (1971).

  5. 5

    Bhattacharjee, J. K. Crit. Rev. Microbiol. 12, 131–151 (1985).

  6. 6

    Ehmann, D. E., Gehring, A. M. & Walsh, C. T. Biochemistry 38, 6171–6177 (1999).

  7. 7

    Praphanphoj, V., Sacksteder, K. A., Gould, S. J., Thomas, G. H. & Geraghty, M. T. Mol. Genet. Metabol. 72, 336–342 (2001).

  8. 8

    Mathews, F. S. Methods Enzymol. 258, 191–216 (1995).

  9. 9

    Flückiger, R., Woodtli, T. & Gallop, P. M. Biochem. Biophys. Res. Commun. 153, 353–358 (1988).

  10. 10

    Kumazawa, T., Seno, H., Urakami, T., Matsumoto, T. & Suzuki, O. Biochim. Biophys. Acta 1156, 62–66 (1992).

Download references

Author information

Correspondence to Tadafumi Kato.

Ethics declarations

Competing interests

The authors declare no competing financial interests.

Rights and permissions

Reprints and Permissions

About this article

Cite this article

Kasahara, T., Kato, T. A new redox-cofactor vitamin for mammals. Nature 422, 832 (2003) doi:10.1038/422832a

Download citation

Further reading


By submitting a comment you agree to abide by our Terms and Community Guidelines. If you find something abusive or that does not comply with our terms or guidelines please flag it as inappropriate.