2-hydroxyisoflavanone synthase, which catalyzes the hydroxylation associated with 1,2-aryl migration of flavanones. Converts liquiritigenin and naringenin into highly unstable precursors of the isoflavones daidzein and genistein. Acts only on substrates with (2S)-chirality. liquiritigenin + O2 + reduced [NADPH--hemoprotein reductase] = (2R,3S)-2,4',7-trihydroxyisoflavanone + H(+) + H2O + oxidized [NADPH--hemoprotein reductase] (2S)-naringenin + O2 + reduced [NADPH--hemoprotein reductase] = 2-hydroxy-2,3-dihydrogenistein + H(+) + H2O + oxidized [NADPH--hemoprotein reductase] Optimum pH is 7.5. Up-regulated upon elicitation. Lys-375 is essential for the intramolecular aryl migration of a flavanone molecule to produce the isoflavonoid skeleton (PubMed:12207646). Arg-104 and Leu-371 are essential for the correct P450 conformation (PubMed:12207646, PubMed:15809082). Belongs to the cytochrome P450 family.