초록
<P>2-Furfurylthiol is the representative aroma compound of Chinese sesame-flavored <I>baijiu</I>. Previous studies demonstrated that <I>baijiu</I> yeasts could generate 2-furfurylthiol using furfural and <SMALL>L</SMALL>-cysteine as precursors and that the <I>Saccharomyces cerevisiae</I> genes <I>STR3</I> and <I>CYS3</I> are closely related to 2-furfurylthiol biosynthesis. To confirm the mechanism of the <I>STR3</I>- and <I>CYS3</I>-gene products on 2-furfurylthiol biosynthesis, their encoded proteins were purified, and we confirmed their activities as carbon-sulfur lyases. Str3p and Cys3p were able to cleave the cysteine-furfural conjugate to release 2-furfurylthiol. Moreover, the characterization of the enzymatic properties of the purified proteins shows good thermal stabilities and wide pH tolerances, which enable their strong potential for various applications. These data provide direct evidence that yeast Str3p and Cys3p release 2-furfurylthiol in vitro, which can be applied to improve <I>baijiu</I> flavor.</P><BR>[FIG OMISSION]</BR>