Feedback inhibition of the prephenate dehydratase from Saccharomyces cerevisiae and its mutation in huangjiu (Chinese rice wine) yeast

Abstract 2-Phenylethanol, an aromatic compound often found in fermented foods, is among the most abundant aromatic compounds in huangjiu (Chinese rice wine). The 2-phenylethanol found in huangjiu is produced by Saccharomyces cerevisiae HJ01, which produces much more 2-phenylethanol than the type strain, S. cerevisiae W303. Feedback regulation of 2-phenylethanol biosynthesis in S. cerevisiae has been carefully studied, except for the behavior of prephenate dehydratase (PDT; EC 4.2.1.51). Mutation (I161K, L239P and Q250H) in PDT were found in S. cerevisiae HJ01, and a structure-based analysis suggested the presence of conserved l -Phe binding sites. The purified PDT from S. cerevisiae strains HJ01 and W303 were found to be inhibited by l -Phe. The specific activity of the PDTHJ01 was 1.27-fold greater than that of the PDTW303. It also showed greater substrate affinity (Km, 11.1–15.9 mM), catalytic efficiency (kcat/Km, 58.9 to 51.7 L/(mmol•s)), and thermal stability, but was less susceptible to feedback inhibition (Ki, 3.97 to 3.35 mM). Thus, mutations in the PDT from S. cerevisiae HJ01 contribute to the higher 2-phenylethanol concentration found in huangjiu.