1969 Volume 22 Issue 5 Pages 183-188
An appropriate concentration of DNP (2, 4-dinitrophenol) is capable of inhibiting the ATP energized mitochondrial volume change induced by gramicidin in the presence of the permeant ions potassium and L-malate. The further addition of the non-mercurial thiol reagent, showdomycin reinstates, an effect of gramicidin which is dependent upon potassium ion. Thus the strategically located nucleophilic mitochondrial thiol group exposed by DNP occupies a pivotal position between two cycles. One of the cycles meshes with the respiratory chain and the other cycle meshes with ATP. This latter cycle contains the site sensitive to gramicidin.