Premium
Two populations of the high‐potential form of cytochrome b ‐559 in chloroplasts treated with 2‐(3‐chloro‐4‐trifluoromethyl)amino‐3,5‐dinitrothiophene (Ant 2p)
Author(s) -
Barabás Klára,
Garab Győző
Publication year - 1989
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(89)80432-6
Subject(s) - dcmu , trifluoromethyl , plastoquinone , chemistry , ant , cytochrome b , stereochemistry , cytochrome , chloroplast , medicinal chemistry , biology , biochemistry , organic chemistry , ecology , gene , alkyl , thylakoid , mitochondrial dna , enzyme
Two populations of the high‐potential form of cytochrome b ‐559 (cyt b ‐559HP) can be distinguished in chloroplasts. In the presence of ≥ 1 μM Ant 2p [2‐(3‐chloro‐4‐trifluoromethyl)anilino‐3,5‐dinitrothiophene] about one‐half of the cyt b ‐559 is autooxidized in the dark. This fraction of cyt b ‐559HP undergoes rapid ( t≈2 ms) photoreduction followed by reoxidation in the dark with t100–200 ms. Photoreduction can be inhibited by DCMU [3‐(3,4‐dichlorophenyl)‐1,1‐dimethylurea] and UHDBT [5‐( n ‐undecyl)‐6‐hydroxy‐4,7‐dioxobezothiazole] but not by DBMIB (2,5‐dibromo‐3‐methyl‐6‐isopropyl‐ p ‐benzoquinine), which suggests the involvement of Q B or the plastoquinone pool. Another fraction of cyt b ‐559HP undergoes slow ( t≥ 1 s), irreversible photooxidation in the presence of ≥ 0.1 μM Ant 2p. The presently available data suggest that the heterogeneity of cyt b ‐559HP originates from PS II α centers.