Enzyme activities of ACO, ACS, and MTN during different tomato fruit development stages. A, In vitro ACO enzyme activity (nmol h−1 mg protein−1); B, in vitro ACS enzyme activity (nmol h−1 mg protein−1); and C, in vitro MTN enzyme activity (nmol h−1 mg protein−1) during tomato fruit development, ripening, and postharvest storage. Error bars represent the sd of the mean of 10 biological replicates. See Figure 2 for maturity stage annotations.