Abstract

The picosecond time resolved absorption spectra of Photosystem 1 (PS1) reaction centres, isolated from pea chloroplasts, have been measured, at room temperature, following excitation by a 10ps optical pulse at 610nm. Energy transfer within PS1 occurs, initially, from excited chlorophyll molecules to P700 (the primary electron donor in the PS1 reaction centre). P700 then undergoes photo-oxidation and initiates a chain of charge transfer reactions that may be summarised as: where A₀ is believed to be a chlorophyll molecule, A₁ is believed to be a quinone species, A₂ is believed to be a specialised iron-sulphur centre and P430 is believed to be two iron-suphur centres.

© 1986 Optical Society of America