This invention relates to isolated polynucleotides encoding enzymes consisting of a carboxypeptidase-like protein, a methyltransferase and a glucosyltransferase, involved in the biosynthesis of β-amyrin-derived triterpenes in plants and seeds. The invention also relates to the construction of recombinant DNA constructs comprising all or a portion of the isolated polynucleotides of the invention, in sense or antisense orientation, operably linked to at least one regulatory sequence.