title: Identification and kinetic study of tyrosinase inhibitors found in sake lees.
abstract: The present study found that the n-hexane extract of freeze-dried sake lees inhibits tyrosinase activity and showed that the constituents isolated from the n-hexane extract are the mixture of triacylglycerols. The inhibitory effects of triolein and trilinolein found as the triacylglycerols were examined using tyrosinases from mushroom and Streptomyces castaneoglobisporus. The IC50 values of the triacylglycerol mixture for the oxidase activity on mushroom and Streptomyces tyrosinases were 20 and 0.14 microg/mL, respectively. The IC50 values of trilinolein for the oxidase activity on mushroom and Streptomyces tyrosinases were 8.4 and 0.1 microM, respectively. However, the inhibitory effect of triolein (IC50=30 microM) was lower than that of trilinolein, even when the Streptomyces tyrosinase was used for the assay. Kinetic analyses indicate that both trilinolein and triolein inhibit the tyrosinase activity noncompetitively. When transformed with a plasmid carrying the Streptomyces tyrosinase gene, the melanin-synthesizing ability of the transformed Escherichia coli host was dose-dependently interfered with by trilinolein.
authors.affiliation: Department of Molecular Microbiology and Biotechnology, Graduate School of Biomedical Sciences, and Frontier Center for Microbiology, Hiroshima University, Kasumi 1-2-3, Minami-ku, Hiroshima 734-8551, Japan.
authors.forename: Hyung Joon
authors.initials: HJ
authors.lastname: Jeon
authors.forename: Masafumi
authors.initials: M
authors.lastname: Noda
authors.forename: Masafumi
authors.initials: M
authors.lastname: Maruyama
authors.forename: Yasuyuki
authors.initials: Y
authors.lastname: Matoba
authors.forename: Takanori
authors.initials: T
authors.lastname: Kumagai
authors.forename: Masanori
authors.initials: M
authors.lastname: Sugiyama
mesh_terms: D000363:Agaricales / Q000201:enzymology; D000434:Alcoholic Beverages / Q000032:analysis*; D004791:Enzyme Inhibitors / Q000032:analysis* / Q000302:isolation & purification; D004926:Escherichia coli / Q000235:genetics; D005511:Food Handling; D005612:Freeze Drying; D007700:Kinetics; D008543:Melanins / Q000096:biosynthesis; D014442:Monophenol Monooxygenase / Q000037:antagonists & inhibitors* / Q000235:genetics / Q000378:metabolism; D011994:Recombinant Proteins / Q000378:metabolism; D013302:Streptomyces / Q000201:enzymology; D014280:Triglycerides / Q000494:pharmacology
chemical_list: D004791:Enzyme Inhibitors; D008543:Melanins; D011994:Recombinant Proteins; D014280:Triglycerides; D014442:Monophenol Monooxygenase; C009564:trilinolein