NADPH → 4-Hydroxybenzaldehyde

Participants

Reaction Steps

5 μl membranes isolated as described in Halkier et al, Archives of Biochemistry and Biophysics 322: 369-377, 1995, from E. coli expressing “12” was reconstituted with 0.225 units NADPH-cytochrome P450-reductase, 50 μg NADPH, 42 nCi p-hydroxyphenylacetaldehyde oxime, and 100 μg dilaurylphosphatidylcholine in a total volume of 100 μl of 30 mM Tricine pH 7.9. After incubation at 30° C. for 30 minutes the reaction mixture was applied to a TLC plate and analyzed as described above. Reconstitution of membranes from E. coli expressing “12” resulted in the accumulation of p-hydroxybenzaldehyde which is the stable dissociation product of p-hydroxymandelonitrile, the last intermediate in the biosynthesis of the cyanogenic glucoside dhurrin. This shows that demonstrates that “12” is the cytochrome P450 that catalyzes the conversion of p-hydroxyphenylacetaldehyde oxime to p-hydroxymandelonitrile. The cDNA is designated P450OX. A clone comprising the described cDNA of P450OX has been deposited on Jan. 10, 1997 with the DSMZ-Deutsche Sammlung von Mikroorganismen und Zellkulturen GmbH, Mascheroder Weg 1b, D-38124 Braunschweig, under the accession number DSM 11367.

Provenance & Evidence