The role of plastoquinone and beta-carotene in the primary reaction of plant photosystem II.
Biochim Biophys Acta
; 459(3): 402-11, 1977 Mar 11.
Article
em En
| MEDLINE
| ID: mdl-849432
ABSTRACT
Extraction of Triton Photosystem II chloroplast fragments with 0.2% methanol in hexane for 3 h results in the removal of 90 to 95% of the plastoquinone in the original preparation. The extracted fragments (chlorophyllplastoquinone ratio, 900 1) showed no P-680 photooxidation at 15 K after a single laser flash. The extracted fragments also showed no light-induced C-550 absorbance change at 77 K. Reconstitution of the primary reaction of Photosystem II, as evidenced by restoration of low-temperature photooxidation of P-680, could be obtained by the addition of plastoquinone A but not by the addition of beta-carotene. The addition of beta-carotene plus plastoquinone A restored the C-550 absorbance change. These results indicate that plastoquinone functions as the primary electron acceptor of Photosystem II and that beta-carotene does not play a direct role in the primary photochemistry but is required for the C-550 absorbance change.
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Coleções:
01-internacional
Base de dados:
MEDLINE
Assunto principal:
Fotofosforilação
/
Quinonas
/
Carotenoides
/
Cloroplastos
/
Plastoquinona
Idioma:
En
Ano de publicação:
1977
Tipo de documento:
Article