Properties of succinate oxidation in tomato fruit mitochondria.

Mitochondria from tomato fruit (Lycopersicon esculentum Mill.) exhibited a respiratory control ratio of 2.5 and an ADP:O ratio of 1.3 for succinate oxidation for 24 hours after isolation. They also showed a delay in response to the first addition of ADP. The addition of ATP and ADP before succinate eliminated the delayed response as did chelation of endogenous cations with ethylenediaminetetraacetic acid. The addition of ATP after succinate resulted in a longer delay in response than that obtained with ADP. Exogenous oxaloacetate in low concentration inhibited respiration in states 3 and 4 with succinate and resulted in delayed response to ADP. The function of adenine nucleotide during the delay in response may be to promote the metabolism of oxaloacetate or to decrease the affinity of oxaloacetate to its site of inhibition.