2-Polyprenyl benzoquinones

Cimino, G., De Stefano, S., and Minale, L. (1972c) Polyprenyl derivatives from the sponge Ircinia spirwsula, 2-polyprenyl-benzoquinones, 2-polyprenylbenzoquinols, prenylated furans and a C-31 difuranoterpene. Tetrahedron, 28,1315-1324. 

A polyprenylated benzoquinone derivative that is a key component in mitochondrial electron transport, and the... 

In 1955, R. A. Morton and associates in Liverpool announced the isolation of a quinone which they named ubiquinone for its ubiquitous occurrence.484 485 It was characterized as a derivative of benzoquinone attached to an unsaturated polyprenyl (isoprenoid) side chain (Fig. 15-24). In fact, there is a family of ubiquinones that from bacteria typically contains six prenyl units in its side chain, while most ubiquinones from mammalian mitochondria contain ten. Ubiquinone was also isolated by F. L. Crane and associates using isooctane extraction of mitochondria. These workers proposed that the new quinone, which they called coenzyme Q, might participate in electron transport. As is described in Chapter 18, this function has been fully established. Both the name ubiquinone and the abbreviation Q are in general use. A subscript indicates the number of prenyl units, e.g., Q10. Ubiquinones can be reversibly reduced to the hydro-quinone forms (Fig. 15-24), providing a basis for their function in electron transport within mitochondria and chloroplasts.486 490... 

The coenzyme QIO is a natural substance belonging to the family of 2,3-dimethoxy-5-methyl-6-polyprenyl-l,4-benzoquinone, widely known as ubiquinone for its ubiquitous occurrence in animal and plant tissues. This coenzyme plays a pivotal biological role in the electron transport chain in both photosynthetic and respiratory processes. " CoQlO has a chnical effect in human congestive heart failure and hypertension. It also augments the compromised irmrnme system and prevents cardiotoxicity of some of the cancer drags. ... 

A family of 2,3-dimethyl-5-polyprenyl-l,4-benzoquinones found in plant tissues. R represents a prenyl side-chain which may be unsubstituted (Plastoquinones), monohydroxylated (Plastoquinone C), monoacylated (Plastoquinone B), or monohydroxylated and monoacylated (Plastoquinone Z).The latter classes appear to be confined to higher plant tissues. 

The naphthoquinones, exemplified in higher plants by the phyllo-quinones, e.g. vitamin Ki 5.49), and in bacteria by the mena-quinones, e.g. vitamin K2 5.50), resemble the benzoquinones (above) in structure and function. The polyprenyl side-chains derive... 

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