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Spectroelectrochemistry of cytochrome b 559 in the D1–D2–Cyt b 559 complex from spinach
Author(s) -
Shibamoto Tadao,
Kato Yuki,
Watanabe Tadashi
Publication year - 2008
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/j.febslet.2008.03.041
Subject(s) - spinach , cytochrome b , chemistry , cytochrome , biochemistry , gene , enzyme , mitochondrial dna
The redox potential of cytochrome b 559 (Cyt b 559) in the D1–D2–Cyt b 559 complex from spinach has been determined to be +90 ± 2 mV vs. SHE at pH 6.0, by thin‐layer cell spectroelectrochemistry for the first time. The redox potential, corresponding uniquely to the so‐called “low‐potential form”, exhibited a sigmoidal pH‐dependence from pH 4.0 to 9.0, ranging from +115 to +50 mV. An analysis of the pH‐dependence based on model equations suggests that two histidine residues coordinating to the heme iron in the protein subunits may exert electrostatic influence on the redox potential of Cyt b 559.