15-CIS-BETA-CAROTENE FOUND IN THE REACTION-CENTER OF SPINACH PHOTOSYSTEM-I

beta-Carotene was extracted from spinach Photosystem I reaction center s (one consisting of the Psa A, B, C, D and E subunits and the other c onsisting of the Psa A and B subunits alone), and the extract was subj ected to high-pressure liquid chromatography using an apparatus equipp ed with a two-dimensional diode-array detector; all the procedures wer e performed at similar to 4 degrees C in complete darkness. Both 15-ci s and all-trans-beta-carotene were identified in the extract by means of electronic absorption spectroscopy. Thus, universal presence of 15- cis carotenoid in the reaction centers of purple photosynthetic bacter ia and of spinach Photosystem I and Photosystem II has been shown.