The rapid restoration of respiratory control to uncoupled mitochondria.

A polarographic technique was used to demonstrate the rapid restoration by bovine serum albumin of respiratory control to rat liver mitochondria uncoupled with various reagents. Albumin also restored respiratory control to mitochondria isolated from animals treated by injection with an uncoupling reagent and to mitochondria incubated with the reagent prior to the polarographic assay. Albumin was effective with the nitroand halo-substituted phenols, thyroxine, Dicumarol, carbonyl cyanide m-chlorophenylhydrazone, and 4,5,6,7-tetrachloro-2-trifluoromethylbenzimidazole. Albumin was ineffective in counteracting the inhibitory action of gramicidin, antimycin A, oligomycin, and rotenone. Although the addition of an amount of albumin equimolar to that of the uncoupling reagent present had a substantial effect, amounts of the protein at least twice equimolar were required for the rapid and essentially complete restoration of respiratory control with most of the reagents tested.