Identification and sequence determination of a cDNA clone for tomato pectin esterase.

Cell wall softening during tomato fruit ripening is brought about through the action of a number of pectolytic enzymes. We have reported previously the cloning and characterisation of the cDNA for the major cell wall softening (degrading) enzyme, polygalacturonase [Grierson, D., Tucker, G. A., Keen, J., Ray, J., Bird, C. R. and Schuch, W. (1986) Nucleic Acids Res. 14, 8595-8603]. We have now isolated a cDNA clone for tomato pectin esterase, an enzyme also implicated in cell wall softening. Here we report the structure of this cDNA and compare it with the structure of pectin esterase derived from amino acid sequence experiments [Markovic, O. and Jornvall, H. (1986) Eur. J. Biochem. 158, 455-462]. We have used the pectin esterase cDNA clone to analyse pectin esterase gene expression during development and ripening of normal and mutant fruit.