|Superclasses:||an aldehyde or ketone → a ketone → a cyclic ketone|
Quinones are organic compounds derived from aromatic compounds, with two carbonyl groups incorporated into the ring structure with rearrangement of the double bonds where necessary. Quinones are conjugated but not aromatic.
A classic example of a quinone is 1,4-benzoquinone. Quinones are commonly named with a prefix that indicates the parent aromatic hydrocarbon (for example, "benzo-" for benzene, "naphtho-" for naphthalene, and "anthra-" for anthracene) with a "-quinone" suffix.
Several types of quinones serve as electron acceptors in electron transport chains. Quinones can carry two electrons, and when fully reduced they are referred to as quinols. The addition of a single H atom to a quinone results in formation of a free radical called a semiquinone.
Many quinone derivatives often have other biological activities, such as vitamin K.
Reactions known to both consume and produce the compound:
Not in pathways:
2 a quinone + NADPH + H+ ↔ 2 a semiquinone + NADP+
In Reactions of unknown directionality:
Not in pathways:
2 a quinone + NADH + H+ = 2 a semiquinone + NAD+
This compound has been characterized as an alternative substrate of the following enzymes: L-aspartate oxidaseInhibits: ArcB + ATP → ArcB-Phis292 + ADP
Cahoon03: Cahoon EB, Hall SE, Ripp KG, Ganzke TS, Hitz WD, Coughlan SJ (2003). "Metabolic redesign of vitamin E biosynthesis in plants for tocotrienol production and increased antioxidant content." Nat Biotechnol 21(9);1082-7. PMID: 12897790
Horvath: Horvath G, Wessjohann L, Bigirimana J, Monica H, Jansen M, Guisez Y, Caubergs R, Horemans N "Accumulation of tocopherols and tocotrienols during seed development of grape (Vitis vinifera L. cv. Albert Lavallee)." Plant Physiol Biochem 44(11-12);724-31. PMID: 17110122
©2016 SRI International, 333 Ravenswood Avenue, Menlo Park, CA 94025-3493