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The activation and inactivation of the Dunaliella salina chloroplast coupling factor 1 (CF 1 ) in vivo and in situ
Author(s) -
Selman-Reimer Susanne,
Selman Bruce R.
Publication year - 1988
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(88)80632-x
Subject(s) - dunaliella salina , in vivo , chloroplast , biophysics , lysis , atpase , biochemistry , halotolerance , atp hydrolysis , chemistry , dunaliella , osmotic shock , atp synthase , enzyme , biology , microbiology and biotechnology , algae , bacteria , botany , gene , genetics
Preillumination of intact cells of the eukaryotic, halotolerant, cell‐wall‐less green alga Dunaliella salina induces a dark ATPase activity the magnitude of which is about 3–5‐fold higher than the ATPase activity observed in dark‐adapted cells. The light‐induced activity arises from the activation and stabilization in vivo of chloroplast coupling factor 1 (CF 1 ). This activity, ∼ 150–300 μmol ATP hydrolyzed/mg Chl per h, rapidly decays (with a half‐time of about 6 min at room temperature) in intact cells but only slowly decays (with a half‐time of about 45 min at room temperature) if the cells are lysed by osmotic shock immediately after illumination. The activated form of the ATPase in lysed cells is inhibited if the membranes are treated with ferri‐ but not ferrocyanide, suggesting that the stabilization of the activated form of CF 1 is due to the reduction of the enzyme in vivo in the light.