No abstract

No abstract

No abstract

A sodium dodecyl sulfate-Photosystem I (PSI) complex has been prepared and characterized with respect to its electron acceptors. Component X and iron-sulfur centers A and B are absent from this preparation but the intermediate electron acceptor (A,) is present. Flash-induced absorbance changes at 25°C show charge separation, followed by a back-reaction with a half-time of 5 ps. The spectrum of the flash-induced change from 350 to 550 nm indicates a contribution from the intermediate electron acceptor, A;, as well as from P700'. EPR studies show that A; is associated with a free-radical signal having a g-value of 2.0025 and a linewidth of 12 gauss. A, would appear to be associated with a monomeric form of either Chl a or pheophytin a. INTRODUCIION Recent kinetic studies utilizing optical and electron paramagnetic resonance (EPR) spectroscopic tech-

No abstract