Last modified: Tue Jul 6 10:11:27 BST 2004

Steroid carbon nomenclature

Trivial names: Ergosterol; Provitamin D2
Systematic name: (22E)-Ergosta-5,7,22-trien-3ß-ol
Molecular formula: C28H44O
CAS Number: 57-87-4
Merck Index (11th Ed) Number: 3607


Pathway: 22,23-Dihydroergosterol -> Ergosterol
Reaction: desaturation of sterol C22-C23 bond (sterol Delta22-desaturation)
Enzyme: P45022DS (ergosterol Delta22-desaturase), CYP61
EC 1.14.99.-


  1. Yoshida, Y. and Aoyama, Y. (1991) Cytochromes P-450 in the ergosterol biosynthesis. In Ruckpaul, K. and Rein, H., Eds. Frontiers in Biotransformation, vol. 4: Microbial and Plant Cytochromes P-450: Biochemical Characteristics, Genetic Engineering and Practical Implications. Taylor & Francis, London, pp. 127-148.
  2. Kelly, S.L., Lamb, D.C., Corran, A.J., Baldwin, B.C., Parks, L.W. and Kelly, D.E. (1995) Purification and reconstitution of activity of Saccharomyces cerevisiae P450 61, a sterol Delta22-desaturase. FEBS Lett. 377, 217-220.

Back to the Directory of P450-containing Systems home page: