On the logic of the application of double-inhibitor titrations for the elucidation of the mechanisms of energy coupling.

In the last couple of years the chemiosmotic hypothesis has been severely criticised, such that many research groups now consider it to be a less than exact description of biological energy transduction. The most potent experimental support for this view is based upon the technique known as the double-inhibitor titration [e.g., (1982) Biochem. J. 206, 351-357]. The results of such experiments have been considered by many to exclude 'unequivocally' the chemiosmotic coupling model. It will be shown that such unequivocal statements are not possible. An argument is put forward which shows how the chemiosmotic model may explain these titrations without any further elaborations of the original hypothesis.