Isolation of mitochondria from soybean leaves on discontinuous percoll gradients.

A technique to isolate mitochondria from chamber-grown soybeans (Glycine max cv Williams) was developed. The mitochondria were isolated by centrifugation on discontinuous Percoll gradients which yielded a sharp band of mitochondria contaminated by only 4% of the total chlorophyll in the gradient. Contamination by peroxisomes was also slight. The isolated mitochondria oxidized malate plus glutamate, NADH, and malate with respiratory control. They also showed cyanide-insensitive, alternative pathway activity which was inhibited by salicylhydroxamic acid.