4-hydroxyphenylacetaldehyde oxime monooxygenase
Class of enzymes
From Wikipedia, the free encyclopedia
4-hydroxyphenylacetaldehyde oxime monooxygenase (EC 1.14.14.37, CYP71E1) is an enzyme that catalyzes a sequence of three chemical reactions that are part of the biosynthesis of the cyanogenic glycoside dhurrin in sorghum.[1][2]
| 4-hydroxyphenylacetaldehyde oxime monooxygenase | |||||||||
|---|---|---|---|---|---|---|---|---|---|
| Identifiers | |||||||||
| EC no. | 1.14.14.37 | ||||||||
| Databases | |||||||||
| IntEnz | IntEnz view | ||||||||
| BRENDA | BRENDA entry | ||||||||
| ExPASy | NiceZyme view | ||||||||
| KEGG | KEGG entry | ||||||||
| MetaCyc | metabolic pathway | ||||||||
| PRIAM | profile | ||||||||
| PDB structures | RCSB PDB PDBe PDBsum | ||||||||
| Gene Ontology | AmiGO / QuickGO | ||||||||
| |||||||||
Reactions catalysed
An earlier enzyme, tyrosine N-monooxygenase, in the pathway to dhurrin converts L-tyrosine to (E)-(4-hydroxyphenyl)acetaldehyde oxime.[2] The first reaction catalysed by 4-hydroxyphenylacetaldehyde oxime monooxygenase isomerises this compound to the (Z) oxime:
-(4-hydroxyphenyl)acetaldehyde_oxime.svg)
(E)-oxime
CYP71E1
-(4-hydroxyphenyl)acetaldehyde_oxime.svg)
(Z)-oxime
The enzyme then catalyses the loss of water from the intermediate (Z)-oxime, giving 4-hydroxyphenylacetonitrile:[2]
Finally, the cytochrome P450 component of the enzyme uses nicotinamide adenine dinucleotide phosphate (NADPH) and molecular oxygen to convert 4-hydroxyphenylacetonitrile to (S)-4-hydroxymandelonitrile.[3][4]
-4-hydroxymandelonitrile.svg)
(S)-4-hydroxymandelonitrile is converted to dhurrin by the enzyme cyanohydrin beta-glucosyltransferase.[2][4]
Classification
The systematic name of this enzyme class is (Z)-4-hydroxyphenylacetaldehyde oxime,NADPH:oxygen oxidoreductase. Other names in common use include 4-hydroxybenzeneacetaldehyde oxime monooxygenase, cytochrome P450II-dependent monooxygenase, NADPH-cytochrome P450 reductase (CYP71E1), CYP71E1, and 4-hydroxyphenylacetaldehyde oxime,NADPH:oxygen oxidoreductase.[1]
