Competitive inhibition of mushroom tyrosinase by 4-substituted benzaldehydes

Departamento de Bioquímica y Biología Molecular A, Unidad Docente de Biología, Facultad de Veterinaria, Universidad de Murcia, E-30080, Murcia, Spain.
Journal of Agricultural and Food Chemistry (Impact Factor: 3.11). 09/2001; 49(8):4060-3. DOI: 10.1021/jf010194h
Source: PubMed

ABSTRACT A kinetic study of the inhibition of mushroom tyrosinase by 4-substituted benzaldehydes showed that these compounds behave as classical competitive inhibitors, inhibiting the oxidation of L-3,4-dihydroxyphenylalanine (L-DOPA) by mushroom tyrosinase (o-diphenolase activity). The kinetic parameter (K(I)) characterizing this inhibition was evaluated for all of the seven compounds assayed. Cuminaldehyde showed the most potent inhibitory activity (K(I) = 9 microM). It also inhibited the oxidation of L-tyrosine by mushroom tyrosinase (o-monophenolase activity) in a competitive manner. The corresponding kinetic parameter for this inhibition was evaluated (K(I) = 0.12 mM).

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    • "It suggested that the position of the substituent influenced the tyrosinase inhibitory potency, and in the investigation, the amide group at the position-4 of the phenyl ring was more efficacious for the inhibitory activity. It was consistent with previous reports by Kubo [17], Jimenez [18]. "
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    European Journal of Medicinal Chemistry 03/2015; 93. DOI:10.1016/j.ejmech.2015.02.013 · 3.43 Impact Factor
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    • "First 300 ȝL of 2.5 mM 3,4-dihydroxyphenylalanine (L-DOPA)solution was added to 700 ȝL of 0.1 M phosphate buffer (pH 7.5). The mixture was preincubated at 37Gfor 5 min and 100 ȝL of potato extract was added, and the reaction was monitored by dopachrome formation at 475 nm (İ = 3700 Mcm -1 ) (Jiménez et al., 2001 "
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    ABSTRACT: Tyrosinase is responsible for the enzymatic browning of fruits and vegetables and usually catalyze the conversion of monophenols to o-diphenols and oxidation of diphenols to corresponding quinines. However, when 3,4-dihydroxymandelic acid is provided as the substrate, it catalyzes the oxidative decarboxylation reaction to generate 3,4-dihydroxybenzaldehyde (protocatechualdehyde, PA. In the present study, tyrosinase was purified from potato with 27.9 purification fold by salting out with ammonium sulfate, DEAE-Sepharose and Sephadex G-150 column chromatography. The purified tyrosinase was confirmed by tyrosinase active staining following SDS-PAGE. Tyrosinase activity was visualized in the gel as a dark band. The molecular weight of tyrosinase from potato was 38kDa as determined by SDS-PAGE. Purified tyrosinase mediated oxidative decarboxylation of 3,4-dihydroxymandelate. The identity of the reaction product, PA was confirmed by high-performance liquid chromatography (HPLC) as well as ultraviolet spectral studies. Phenol oxidase inhibitors such as potassium cyanide, sodium azide, and phenylthiourea inhibited the participation of the active site copper of the enzyme in the catalysis.
    Horticulture, Environment and Biotechnology 08/2012; 53(4). DOI:10.1007/s13580-012-0098-z · 0.49 Impact Factor
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    • "에 정리하였다. 앞서와 같이, 기질분자 중 hydroxyl-치환기들은 수용체의 반응점 내 구리원자와의 배위결합으로 인한 비경쟁적 인 저해반응[Neeley 등, 2009]과 반응점 주변의 아미노산 잔기 들 사이의 수소결합으로 인한 경쟁적인 저해반응[Mercedes 등, 2000]에 관여하여 안정한 기질-수용체 착 화합물 "
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    ABSTRACT: Molecular docking of polyhydroxy substituted flavone analogues (1-25) as substrate molecules to the active site of tyrosinase (PDB ID: Deoxy-form (2ZMX) & Oxy-form (1WX2)) and Free-Wilson analysis were studied to understand the roles of hydroxyl substituents () in substrate molecules for the tyrosinase inhibitory activation. It is founded from Free-Wilson analysis that the =hydroxyl among substituents had the strongest influence on the tyrosinase inhibitory activity. H-bonds between the hydroxyl substituents of substrate molecules and amino acid residues in the active site of tyrosinase were contributed to make a stable substrate-receptor complex compound. Particularly, it is proposed from the findings that the noncompetitive inhibitory activation would take place via H-bonding between peroxide oxygen (Per404) atom in the active site of tyrosinase and the hydroxyl substituents in substrate molecule.
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