Inhibition of O2 Consumption Resistant to Cyanide and Its Development by N-Propyl Gallate and Salicylhydroxamic Acid

摘要

Kinetics of inhibition of cyanide-insensitive O2 uptake by n-propyl gallate (PG) and salicylhydroxamic acid (SHAM) were determined in fresh slices from ethylene-treated tubers of Solanum tuberosum `Norchip' and with mitochondria and lipoxygenase (EC 1.13.11.12) isolated from these tubers. PG and SHAM appeared to be inhibiting at identical sites in mitochondria but at disparate sites in slices. The apparent KI for SHAM was similar in mitochondria and slices. However, the apparent KI for PG in mitochondria was about 40-fold lower than the KI for PG inhibition of lipoxygenase activity. The amount of lipoxygenase associated with mitochondria increased when tubers were treated with ethylene. PG, but not SHAM, inhibited aging-induced development of cyanide-insensitive respiration. The latter two phenomena are in accord with the hypothesis that lipid metabolism is required for the development of the alternative pathway.