DIOXYGENASES: Molecular Structure and Role in Plant Metabolism.
Dioxygenases are nonheme iron-containing enzymes important in the biosynthesis of plant signaling compounds such as abscisic acid, gibberellins, and ethylene and also of secondary metabolites, notably flavonoids and alkaloids. Plant dioxygenases fall into two classes: lipoxygenases and 2-oxoacid-dependent dioxygenases. The latter catalyze hydroxylation, epoxidation, and desaturation reactions; some enzymes catalyze more than one type of reaction in successive steps in a biosynthetic pathway. This review highlights recent discoveries on both enzyme groups, particularly in relation to gibberellin biosynthesis, in vivo activity of 1-aminocyclopropane-1-carboxylate oxidase, and molecular structure/function relationships. Similarities between the roles of monooxygenases and dioxygenases are also discussed.
Prescott
Andy G.
AG
Department of Applied Genetics, John Innes Centre, Norwich Research Park, Colney Lane, Norwich NR4 7UH, United Kingdom, Department of Agricultural Botany, Plant Science Laboratories, The University of Reading, Reading RG6 2AS, United Kingdom.
John
Philip
P