Pigment stoichiometries in the D1/D2/cytochrome b-559 reaction center complex from spinach have been studied by spectrophotometry and normalphase silica HPLC of the solvent extracts. Based on the well-accepted molar ratio Pheo a/P680 = 2, the results are summarized by Chl a/P680 = 6.01 ± 0.37 (n = 24) and β-carotene/P680= 1.84 ± 0.11 (n = 4). These stoichiometries are significantly different from those of bacterial reaction center complexes.
