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Pigment stoichiometry of a newly isolated D1—D2—Cyt b 559 complex from the higher plant Beta vulgaris L
Author(s) -
Montoya G.,
Yruela I.,
Picorel R.
Publication year - 1991
Publication title -
febs letters
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.593
H-Index - 257
eISSN - 1873-3468
pISSN - 0014-5793
DOI - 10.1016/0014-5793(91)80601-x
Subject(s) - pheophytin , absorbance , stoichiometry , chemistry , elution , pigment , chlorophyll , chlorophyll a , nuclear chemistry , chromatography , biochemistry , organic chemistry , photosynthesis , photosystem ii
Two D1‐D2‐Cyt b 559 complexes with different pigment stoichiometry were isolated from the higher plant B. vulgaris . The procedures for isolating both complexes only differed in the washing time of the DEAE column with 50 mM Tris‐HCl, pH 7.2, 0.05% Triton X‐100 and 30 mM NaCl. When the column was washed until the eluate had an absorbance of 0.01 at 670 nm, the isolated D1—D2—Cyt b 559 complex presented a pigment stoichiometry of 6 chlorophyll a , 2 β‐carotene, and 1 cytochrome b 559 per 2 pheophytin a . In contrast, when the column was exhaustively washed until the eluate reached an absorbance of 0.005 at 670 nm, the complex had a stoichiometry of 4 chlorophyll a , 1 β‐carotene, and 1 cytochrome b 559 per 2 pheophytin a . We think that the former stoichiometry corresponds to that of the native D1—D2—Cyt b 559 complex. Moreover, both preparations showed 2 mol of pheophytin a per 1 mol of reaction center protein.