Mechanistic aspects of CYP74 allene oxide synthases and related cytochrome P450 enzymes

• Published in: Phytochemistry (Oxford) Vol. 70; no. 13; pp. 1522 - 1531
• Main Author: Brash, Alan R.
• Format: Journal Article
• Language: English
• Published: England Elsevier Ltd 01.09.2009
• Subjects: Aldehyde-Lyases - metabolism; Allene oxide; Allene oxide synthase; binding sites; Catalytic cycle; chemical reactions; Compound I; Compound II; CYP74; cysteine; cytochrome P-450; Cytochrome P-450 Enzyme System - metabolism; Cytochrome P450; Divinyl ether synthase; enzyme activity; enzyme substrates; Fatty acid hydroperoxide; fatty acid peroxide; heme; Hydroperoxide lyase; hydroperoxides; Intramolecular Oxidoreductases - metabolism; isomerases; literature reviews; Mechanism; Models, Biological; oxidoreductases; oxygenases; Plant Proteins - metabolism; Plants - enzymology; Plants - metabolism; Prostacyclin synthase; structure-activity relationships; substrate specificity; Thromboxane synthase; Thromboxane-A Synthase - metabolism; AOS; HPL; Hydroperoxide lyase; Compound II; Cytochrome P450; Allene oxide; PGI 2; CYP74; Mechanism; Allene oxide synthase; Fatty acid hydroperoxide; DES; Thromboxane synthase; EAS; TxA 2; Compound I; Prostacyclin synthase; Divinyl ether synthase; Catalytic cycle
• ISSN: 0031-9422; 1873-3700
• DOI: 10.1016/j.phytochem.2009.08.005

The CYP74 enzymes using fatty acid hydroperoxides as substrate have mechanisms in close parallel with CYP5 and CYP8A in mammalian biology, and in many respects with conventional P450 monooxygenases. The existence of CYP5, CYP8A, and the CYP74 enzymes specialized for reaction with fatty acid peroxide substrates presents opportunities for a “different look” at the catalytic cycle of the cytochrome P450s. This review considers how the properties of the peroxide-metabolizing enzymes are distinctive, and how they tie in with those of the conventional monooxygenase enzymes. Some unusual reactions of each class have parallels in the other. As enzyme reactions and P450 structures emerge there will be possibilities for finding their special properties and edging this knowledge into the big picture.