title: The first cytochrome P450 in ferns. Evidence for its involvement in phytoecdysteroid biosynthesis in Polypodium vulgare.
abstract: The fern Polypodium vulgare is a phytoecdysteroid (PE)-producing plant. Cultures of P. vulgare prothalus produce PE, whereas prothalus-derived callus cultures do not. However, this callus line can transform topically applied ecdysone (E) to 20-hydroxyecdysone (20E), which is the last step in the biosynthetic pathway of the main plant PE. This hydroxylation is catalysed by a cytochrome P450 enzyme. E treatment of the callus line results in an increased amount of P450, showing a linear correspondence between the amount of P450 and in vivo E 20-hydroxylation activity, estimated by measuring the bioconversion of E to 20E. This activity can be inhibited by molecules that bind to the P450-heme group. E shows a P450-substrate-binding spectrum with microsomes that overexpress the P450 protein. Finally, a P450 protein was purified from E-treated calli, this being the first P450 to be described in the pterydophyte group.
authors.affiliation: Department of Biological Organic Chemistry, IIQAB-CSIC, Barcelona, Spain.
authors.forename: Daniel
authors.initials: D
authors.lastname: Canals
authors.forename: Josep
authors.initials: J
authors.lastname: Irurre-Santilari
authors.forename: Josefina
authors.initials: J
authors.lastname: Casas
mesh_terms: D002460:Cell Line; D003577:Cytochrome P-450 Enzyme System / Q000378:metabolism*; D004440:Ecdysone / Q000378:metabolism; D026461:Ecdysteroids / Q000096:biosynthesis*; D029624:Ferns / Q000166:cytology / Q000201:enzymology / Q000378:metabolism; D006900:Hydroxylation; D010840:Phytosterols / Q000378:metabolism; D010940:Plant Proteins / Q000378:metabolism; D032494:Polypodium / Q000166:cytology / Q000201:enzymology* / Q000378:metabolism
chemical_list: D026461:Ecdysteroids; D010840:Phytosterols; D010940:Plant Proteins; C021238:phytoecdysones; D004440:Ecdysone; D003577:Cytochrome P-450 Enzyme System