title: Experimental evidence suggesting that H2O2 is produced within the thylakoid membrane in a reaction between plastoquinol and singlet oxygen.
abstract: Plastoquinol (PQH2-9) and plastoquinone (PQ-9) mediate photosynthetic electron transfer. We isolated PQH2-9 from thylakoid membranes, purified it with HPLC, subjected the purified PQH2-9 to singlet oxygen ((1)O2) and analyzed the products. The main reaction of (1)O2 with PQH2-9 in methanol was found to result in formation of PQ-9 and H2O2, and the amount of H2O2 produced was essentially the same as the amount of oxidized PQH2-9. Formation of H2O2 in the reaction between (1)O2 and PQH2-9 may be an important source of H2O2 within the lipophilic thylakoid membrane.
authors.affiliation: Department of Biochemistry/Molecular Plant Biology, University of Turku, FI-20014 Turku, Finland.
authors.forename: Sergey A
authors.initials: SA
authors.lastname: Khorobrykh
authors.affiliation: Laboratory of Organic Chemistry and Chemical Biology, Department of Chemistry, University of Turku, FI-20014 Turku, Finland.
authors.forename: Maarit
authors.initials: M
authors.lastname: Karonen
authors.affiliation: Department of Biochemistry/Molecular Plant Biology, University of Turku, FI-20014 Turku, Finland. Electronic address: esatyy@utu.fi.
authors.forename: Esa
authors.initials: E
authors.lastname: Tyystjärvi
mesh_terms: D028464:Cucurbita / Q000166:cytology / Q000378:metabolism; D006861:Hydrogen Peroxide / Q000378:metabolism*; D010084:Oxidation-Reduction; D018515:Plant Leaves / Q000166:cytology / Q000378:metabolism; D010971:Plastoquinone / Q000031:analogs & derivatives* / Q000378:metabolism; D026082:Singlet Oxygen / Q000378:metabolism*; D020524:Thylakoids / Q000378:metabolism*
chemical_list: D026082:Singlet Oxygen; C003165:plastoquinol; D006861:Hydrogen Peroxide; D010971:Plastoquinone
keywords: Hydrogen peroxide; Photosystem II; Plastoquinone; Singlet oxygen; Thylakoid membrane