In attempt to know the effect of 2, 4, 5-T on energy metabolism, the following re-sults were obtained.
1. 2, 4, 5-T inhibited the oxygen uptake of mouse liver slices at the concentrations of 10-4M to 10-3M. Lower than 10-5M, it seemed to be indifferent to the oxygen uptake.
2. At the concentrations of 5×10-5M to 5×10-4M, 2, 4, 5-T was shown to be an un-coupling agent for oxidative phosphorylation and to stimulate the respiration of rat liver mitochondria in the medium lacking hexukinase.
3. The latent ATPase of the intact mitochondria was activated by 2, 4, 5-T and oligomycin diminished its effect.
4. With various respiratory-chain inhibitors and artificial electron doners and acceptors, it has been demonstrated that 2, 4, 5-T interfered the phosphorylation mechanism equally at any one of the three phosphorylation sites.
Upon these observations, mechanism and site of action of 2, 4, 5-T have been briefly discussed.