ISOLATION AND PROPERTIES OF A PROTEIN FROM CHLOROPLASTS REQUIRED FOR PHOSPHORYLATION AND H+ UPTAKE

: A soluble protein, which is obligatorily required for both H+ uptake and photophosphorylation in chloroplasts but which contains no trypsin-activated adenosine triphosphatase activity is readily extracted from chloroplasts by ethylenediaminetetraacetic acid. Purification of this protein, CFc, has been achieved and it appears that a single protein is required both for H+ uptake and phosphorylation. Addition of the purified factor to ethylenediaminetetraacetic acid treated chloroplasts under hypotonic conditions results in 100% restoration of phosphorylation, complete restoration of the ability of the ethylenediaminetetraacetic acid chloroplasts to accumulate H+ in light as well as restores the ability of trypsin to activate adenosine triphosphatase in the reconstituted ethylenediaminetetraacetic acid chloroplasts. The factor has been identified as CF1, but which probably contains bound Mg2+ or other divalent cations. © 1969, American Chemical Society. All rights reserved.