E. Pinet et al., TENTOXIN HAS AT LEAST 2 BINDING-SITES ON CF1 AND EPSILON-DEPLETED CF1ATPASES ISOLATED FROM SPINACH CHLOROPLAST, FEBS letters, 395(2-3), 1996, pp. 217-220
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
.