TENTOXIN HAS AT LEAST 2 BINDING-SITES ON CF1 AND EPSILON-DEPLETED CF1ATPASES ISOLATED FROM SPINACH CHLOROPLAST

A new procedure for synthesis of C-14-labeled tentoxin [C-14-MePhe[(Z) Delta](3)-tentoxin], with a high specific activity, is described. Bind ing experiments with CF1 or CF1-epsilon isolated from spinach chloropl ast have been carried out using equilibrium dialysis technique. The re sults show the presence of tno classes of binding sites. The associati on constants of the two major binding sites were derived from non-line ar fitting of the binding curves. At 4 degrees C, the first binding si te has a value of K-a1 = 8.2 x 10(5) M(-1) in CF1 and 8.7 x 10(5) M(-1 ) in CF1-epsilon, while the second binding site has lower affinity wit h K-a2 = 1.5 x 10(4) M(-1) in CF1 and 2.3 x 10(3) M(-1) in CF1-epsilon .