Hydrogen peroxide photoproduction by free and immobilized spinach thylakoids A.
Year: 1986
Type: article
Abstract: Spinach thylakoids were used to reduce oxygen to hydrogen peroxide in a reaction catalyzed by riboflavin, which accepts electrons at or near the terminal acceptor of photosystem I. Thylakoids were immobilized in supports such as alginate and agar gels, bovine serum albumin and gelatin foams, and urethane polymers. In all supports H 2 O 2 formation was demonstrated; agar-immobilized thylakoids provided a final peroxide yield equal or greater than that obtained with free thylakoids. A major drawback was inactivation of the system because of photoinhibition of photosystem II; the riboflavin-mediated oxygen uptake rate by photosystem I alone was unaffected, while that of the complete electron transport chain from water was inhibited within 15 min. The photoinhibition problem was partially solved by donating electrons from ascorbate-reduced DCPIP in the photosynthetic electron transport chain at photosystem I, so bypassing photosystem II. We have developed a continuous flow-system containing agar-immobilized thylakoids, in which H 2 O 2 photoproduction with electrons from reduced DCPIP could be sustained for more than 3 h.
Institution: King's College London
Language: English
Subfield: Molecular Biology
Domain: Life Sciences
Open Access status: hybrid
OpenAlex ID: W4402019638