title: Identifying 8-hydroxynaringenin as a suicide substrate of mushroom tyrosinase.
abstract: A biotransformed metabolite of naringenin was isolated from the fermentation broth of Aspergillus oryzae, fed with naringenin, and identified as 8-hydroxynaringenin based on the mass and (1)H- and (13)C-NMR spectral data. The compound showed characteristics of both an irreversible inhibitor and a substrate of mushroom tyrosinase in preincubation and HPLC analysis. These results demonstrate that 8-hydroxynaringenin belongs to a suicide substrate of mushroom tyrosinase. The partition ratio between the compound's molecules in the formation of product and in the inactivation of the enzyme was determined to be 283 +/- 21. The present study's results, together with our previous findings, which proved that both 8-hydroxydaidzein and 8-hydroxygenistein are suicide substrates of mushroom tyrosinase, show that 7,8,4'-trihydroxyl functional groups on flavonoids' skeletons play important roles in producing suicide substrate properties toward mushroom tyrosinase.
authors.affiliation: Department of Biological Science and Technology, National University of Tainan, Tainan, Taiwan.
authors.forename: Te-Sheng
authors.initials: TS
authors.lastname: Chang
authors.forename: Meng-Yi
authors.initials: MY
authors.lastname: Lin
authors.forename: Hsuan-Jung
authors.initials: HJ
authors.lastname: Lin
mesh_terms: D001236:Aspergillus oryzae / Q000201:enzymology / Q000378:metabolism*; D044950:Flavanones / Q000737:chemistry / Q000378:metabolism*; D013058:Mass Spectrometry; D014442:Monophenol Monooxygenase / Q000037:antagonists & inhibitors / Q000378:metabolism*; D019906:Nuclear Magnetic Resonance, Biomolecular
chemical_list: D044950:Flavanones; D014442:Monophenol Monooxygenase; C005273:naringenin