title: The effect of thiobarbituric acid on tyrosinase: inhibition kinetics and computational simulation.
abstract: Tyrosinase plays various roles in organisms and much research has focused on the regulation of tyrosinase activity. We studied the inhibitory effect of thiobarbituric acid (TBA) on tyrosinase. Our kinetic study showed that TBA inhibited tyrosinase in a reversible noncompetitive manner (K(i) 5 14.0 ± 8.5 mM and IC₅₀ 5 8.0 ± 1.0 mM). Intrinsic and ANS-binding fluorescences studies were also performed to gain more information regarding the binding mechanism. The results showed that no tertiary structural changes were obviously observed. For further insight, we predicted the 3D structure of tyrosinase and simulated the docking between tyrosinase and TBA. The docking simulation was successful with significant scores (binding energy for AutoDock4: -5.52 kcal/mol) and suggested that TBA was located in the active site. The 11 ns molecular dynamics simulation convinced that the four HIS residues (residue numbers: 57, 90, 250, and 282) were commonly responsible for the interaction with TBA. Our results provide a new inhibition strategy that works using an antioxidant rather than targeting the copper ions within the tyrosinase active site.
authors: College of Biological and Environmental Sciences, Zhejiang Wanli University, Ningbo 315100, P. R. China.
authors: Shang-Jun
authors: SJ
authors: Yin
authors: Yue-Xiu
authors: YX
authors: Si
authors: Zhi-Jiang
authors: ZJ
authors: Wang
authors: Su-Fang
authors: SF
authors: Wang
authors: Sangho
authors: S
authors: Oh
authors: Sanghyuk
authors: S
authors: Lee
authors: Seon-Mi
authors: SM
authors: Sim
authors: Jun-Mo
authors: JM
authors: Yang
authors: Guo-Ying
authors: GY
authors: Qian
authors: Jinhyuk
authors: J
authors: Lee
authors: Yong-Doo
authors: YD
authors: Park
mesh_terms: D020134:Catalytic Domain; D002478:Cells, Cultured; D003198:Computer Simulation; D003300:Copper / Q000737:chemistry / Q000378:metabolism; D004305:Dose-Response Relationship, Drug; D006801:Humans; D007700:Kinetics; D008958:Models, Molecular; D014442:Monophenol Monooxygenase / Q000037:antagonists & inhibitors* / Q000737:chemistry* / Q000378:metabolism; D011487:Protein Conformation; D013329:Structure-Activity Relationship; D013858:Thiobarbiturates / Q000737:chemistry / Q000494:pharmacology*
chemical_list: D013858:Thiobarbiturates; D003300:Copper; D014442:Monophenol Monooxygenase; C029684:thiobarbituric acid