Département de chimie moléculaire

We describe 2-mercaptopyridine-N-oxide (HSPNO) as a new and efficient competitive inhibitor of mushroom tyrosinase (KIC=3.7 $μ$). Binding studies of HSPNO and 2-hydroxypyridine-N-oxide (HOPNO) on dinuclear copper(II) complexes [Cu2(BPMP)($μ$-OH)](ClO4)2 (1; HBPMP=2,6-bis[bis(2-pyridylmethyl)aminomethyl]-4-methylphenol) and [Cu2(BPEP)($μ$-OH)](ClO4)2 (2; HBPEP=2,6-bis{\{}bis[2-(2-pyridyl)ethyl]aminomethyl{\}}-4-methylphenol), known to be functional models for the tyrosinase diphenolase activity, have been performed. A combination of structural data, spectroscopic studies, and DFT calcns. evidenced the adaptable binding mode (bridging vs. chelating) of HOPNO in relation to the geometry and chelate size of the dicopper center. For comparison, binding studies of HSPNO and kojic acid (5-hydroxy-2-(hydroxymethyl)-4-pyrone) on dinuclear complexes were performed. A theor. approach has been developed and validated on HOPNO adducts to compare the binding mode on the model complexes. It has been applied for HSPNO and kojic acid. Although results for HSPNO were in line with those obtained with HOPNO, thus reflecting their chem. similarity, we showed that the bridging mode was the most preferential binding mode for kojic acid on both complexes. [on SciFinder(R)]