Purification and properties of two pectinesterases from tomatoes.

Pectinesterase is present in green tomato fruit and increases several-fold during ripening. Several isoenzymes of pectinesterase are known to exist in tomatoes, but one isoenzyme predominates in the fruit of most cultivars. A few cherry tomato cultivars have been identified that contain low levels of this isoenzyme and much higher levels of another pectinesterase that is unique to those cultivars. The two major pectinesterases were purified to homogeneity and characterized. There were significant differences in the pectinesterases but they cross-reacted with antibodies raised against them and their N-terminal amino acid sequences were similar.