Title: Plastoquinones
Additional Names: PQs
Literature References: Family of lipid-soluble benzoquinone derivatives involved in photosynthetic electron transport. Structurally and functionally analogous to the ubiquinones, q.v. Structures are characterized by a side chain of repeating isoprenoid units with 9 units being the most common. Originally discovered by Kofler in 1946. Isoln of PQ-9 from alfalfa: F. L. Crane, Plant Physiol. 34, 546 (1959). Localization in chloroplasts and role in photosynthesis: N. I. Bishop, Proc. Natl. Acad. Sci. USA 45, 1696 (1959). Structure: M. Kofler et al., Helv. Chim. Acta 42, 2252 (1959); N. R. Trenner et al., J. Am. Chem. Soc. 81, 2026 (1959). Synthesis: C. H. Shunk et al., ibid. 5000. Identification of plastoquinone analogs B and C: L. P. Kegel et al., Biochem. Biophys. Res. Commun. 8, 294 (1962). Review of role in photosynthetic electron flow: U. Siggel, Bioelectrochem. Bioenerg. 3, 302-318 (1976); A. Trebst in Coenzyme Q, G. Lenaz, Ed. (John Wiley & Sons, Chichester, 1985) pp 257-284.
Derivative Type: Plastoquinone 9
CAS Registry Number: 4299-57-4
CAS Name: (all-E)-2,3-Dimethyl-5-(3,7,11,15,19,23,27,31,35-nonamethyl-2,6,10,14,18,22,26,30,34-hexatriacontanonaenyl)-2,5-cyclohexadiene-1,4-dione
Additional Names: 2,3-dimethyl-5-solanesyl-1,4-benzoquinone; Kofler's quinone; plastoquinone A; plastoquinone 45; Q-254; PQ-9
Molecular Formula: C53H80O2
Molecular Weight: 749.20
Percent Composition: C 84.97%, H 10.76%, O 4.27%
Properties: Yellow crystals, mp 48-49°. uv max (isooctane): 254, 262 nm (E 1cm1% 247, 226).
Melting point: mp 48-49°
Absorption maximum: uv max (isooctane): 254, 262 nm (E 1cm1% 247, 226)
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