Dehydratase that mediates the biosynthesis of isoflavonoids. Can use both 4'-hydroxylated and 4'-methoxylated 2-hydroxyisoflavanones as substrates. Has also a slight carboxylesterase activity toward p-nitrophenyl butyrate. (2R,3S)-2,4',7-trihydroxyisoflavanone = daidzein + H(+) + H2O 2-hydroxy-2,3-dihydrogenistein = genistein + H(+) + H2O a carboxylic ester + H2O = a carboxylate + an alcohol + H(+) kcat is 1.6 sec(-1) with 2,7-dihydroxy-4'-methoxyisoflavanone, 5.3 sec(-1) with 2,7,4'-trihydroxyisoflavanone and 18.1 sec(-1) with 2,5,7,4'-tetrahydroxyisoflavanone as substrates, respectively (at pH 7.5 and 30 degrees Celsius). Secondary metabolite biosynthesis; flavonoid biosynthesis. Belongs to the 'GDXG' lipolytic enzyme family.