Plastoquinone

Structural formula
General
Surname	Plastoquinone
other names	Plastoquinone PQ-9
Molecular formula	C 53 H 80 O 2
Brief description	light yellow leaves
External identifiers / databases
CAS number 4299-57-4 PubChem 5375177 ChemSpider 4938558 Wikidata Q133594
properties
Molar mass	749.20 g mol −1
safety instructions
GHS hazard labeling no classification available
As far as possible and customary, SI units are used. Unless otherwise noted, the data given apply to standard conditions .

Plastoquinone (abbreviated PQ from English plastoquinone ) is a chemical compound belonging to the group of quinones that occurs in the thylakoid membranes of chloroplasts . Here it is involved in the light reaction of photosynthesis by transporting electrons from photosystem II to the cytochrome b ₆ f complex as a link in an electron transport chain .

Molecular structure

The main body of the plastoquinone is 1,4-benzoquinone , which belongs to the quinone group and contains a methyl group in positions 2 and 3 and an isoprenoid side chain in position 5 . Plastoquinone is also referred to as PQ-9 based on the number of isoprene units in the side chain. This hydrophobic side chain enables the connection to be anchored in the likewise hydrophobic area of ​​the thylakoid biomembrane .

The reduction of plastoquinone ( 1 ) to plastoquinol ( 3 ) takes place via the semiquinone ( 2 ).

See also

• Ubiquinone

Individual evidence

1. ↑ Entry on Plastoquinones. In: Römpp Online . Georg Thieme Verlag, accessed on December 28, 2014.
2. ↑ This substance has either not yet been classified with regard to its hazardousness or a reliable and citable source has not yet been found.