Isolation and properties of a natural inhibitor of the chloroplast adenosine triphosphatase

The authors demonstrate that a chloroplast ATPase protein inhibitor could be solubilized by heat treatment of the chloroform-released 7 subunit enzyme or any of the preparations containing the 10,000 M sub(r) subunit. C sub(2) (6). The properties of this inhibitor were studied. It was sensitive to trypsin. It inhibited membrane-bound chlorophast Mg super(2+)- ATPase and soluble CF sub(1)-ATPase. This inhibition was pH-dependent and was stimulated by Mg super(2+) and ATP. It did not inhibit the particulate or soluble mitochondrial ATPase activity from bovine heart or insect flight muscles.