Benzonitriles as tyrosinase inhibitors with hyperbolic inhibition manner
1Department of Applied Biological Chemistry, School of Agriculture, Utsunomiya University, Utsunomiya, Tochigi 321-0943, Japan.
Abstract:
As a novel mushroom tyrosinase inhibitor, 4-methoxybenzonitrile (anisnitrile) was identified (IC50 = 111.1 μM) with hyperbolic inhibition manner. The calculated αKi (166.3 μM) was larger than Ki (66.5 μM) by Dixon plots, indicating that this nitrile acts as a competitive-noncompetitive mixed type inhibitor. Similarly, 4-isopropylbenzonitrile (cuminnitrile) partially inhibited the oxidation catalyzed by tyrosinase (IC50 = 121.5 μM, Ki = 88.8 μM, and αKi = 239.8 μM). Nine other benzonitriles also exhibited partial tyrosinase-inhibitory activity. In particular, 4-methylbenzonitrile (IC50 = 79.9 μM) is considered to be the most potent among the tested benzonitriles. Benzonitriles barely caused intermolecular amidine formation under physiologic conditions. Furthermore, they possibly coordinate copper at the active site of tyrosinase. Hence, benzonitriles exhibit different inhibition characteristics as compared with that exhibited by benzaldehydes.
Related Concept Videos
Hyperbolic and Inverse Hyperbolic Functions: Problem Solving
Hyperbolic Functions
Eukaryotic Transcription Inhibitors
Eukaryotic transcription inhibitors usually contain two distinct domains, a...
Inverse Hyperbolic Functions and Their Derivatives
Feedback Inhibition
Enzyme Inhibition


