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Inhibitory effect of phthalic Acid on tyrosinase: the mixed-type inhibition and docking simulations.

Yin SJ, Si YX, Qian GY - Enzyme Res (2011)

Bottom Line: For probing effective inhibitors of tyrosinase, a combination of computational prediction and enzymatic assay via kinetics was important.Simulation was successful (binding energies for Dock6.3 = -27.22 and AutoDock4.2 = -0.97 kcal/mol), suggesting that PA interacts with LEU73 residue that is predicted commonly by both programs.The present study suggested that the strategy of predicting tyrosinase inhibition based on hydroxyl groups and orientation may prove useful for screening of potential tyrosinase inhibitors.

View Article: PubMed Central - PubMed

Affiliation: College of Biological and Environmental Sciences, Zhejiang Wanli University, Ningbo 315100, China.

ABSTRACT
Tyrosinase inhibition studies are needed due to the medicinal applications such as hyperpigmentation. For probing effective inhibitors of tyrosinase, a combination of computational prediction and enzymatic assay via kinetics was important. We predicted the 3D structure of tyrosinase, used a docking algorithm to simulate binding between tyrosinase and phthalic acid (PA), and studied the reversible inhibition of tyrosinase by PA. PA inhibited tyrosinase in a mixed-type manner with a K(i) = 65.84 ± 1.10 mM. Measurements of intrinsic and ANS-binding fluorescences showed that PA induced changes in the active site structure via indirect binding. Simulation was successful (binding energies for Dock6.3 = -27.22 and AutoDock4.2 = -0.97 kcal/mol), suggesting that PA interacts with LEU73 residue that is predicted commonly by both programs. The present study suggested that the strategy of predicting tyrosinase inhibition based on hydroxyl groups and orientation may prove useful for screening of potential tyrosinase inhibitors.

No MeSH data available.


Related in: MedlinePlus

Intrinsic fluorescence changes by PA. Tyrosinase was incubated with PA for 3 h before measurements. Label 1 represents the native state. Labels 2 through 9 indicate PA concentrations of 1.56, 3.125, 6.25, 12.5, 25, 50, 100, and 400 mM, respectively.
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fig5: Intrinsic fluorescence changes by PA. Tyrosinase was incubated with PA for 3 h before measurements. Label 1 represents the native state. Labels 2 through 9 indicate PA concentrations of 1.56, 3.125, 6.25, 12.5, 25, 50, 100, and 400 mM, respectively.

Mentions: Next, we measured the intrinsic fluorescence changes of tyrosinase in the presence of PA. We found that the intrinsic fluorescence of tyrosinase is changed significantly accompanying a quenching effect, which gradually decreased with no significant shift of the maximum peak wavelength (Figure 5). At 400 mM, PA completely quenched the fluorescence. For calculating binding affinity, a double reciprocal plot was evaluated according to (4) as shown in Figure 6. The result revealed a linear relationship, we calculated the binding constant to be K = 0.068 ± 0.03 mM−1, and the binding number was n = 1.01 ± 0.65 by using (4).


Inhibitory effect of phthalic Acid on tyrosinase: the mixed-type inhibition and docking simulations.

Yin SJ, Si YX, Qian GY - Enzyme Res (2011)

Intrinsic fluorescence changes by PA. Tyrosinase was incubated with PA for 3 h before measurements. Label 1 represents the native state. Labels 2 through 9 indicate PA concentrations of 1.56, 3.125, 6.25, 12.5, 25, 50, 100, and 400 mM, respectively.
© Copyright Policy - open-access
Related In: Results  -  Collection

Show All Figures
getmorefigures.php?uid=PMC3102342&req=5

fig5: Intrinsic fluorescence changes by PA. Tyrosinase was incubated with PA for 3 h before measurements. Label 1 represents the native state. Labels 2 through 9 indicate PA concentrations of 1.56, 3.125, 6.25, 12.5, 25, 50, 100, and 400 mM, respectively.
Mentions: Next, we measured the intrinsic fluorescence changes of tyrosinase in the presence of PA. We found that the intrinsic fluorescence of tyrosinase is changed significantly accompanying a quenching effect, which gradually decreased with no significant shift of the maximum peak wavelength (Figure 5). At 400 mM, PA completely quenched the fluorescence. For calculating binding affinity, a double reciprocal plot was evaluated according to (4) as shown in Figure 6. The result revealed a linear relationship, we calculated the binding constant to be K = 0.068 ± 0.03 mM−1, and the binding number was n = 1.01 ± 0.65 by using (4).

Bottom Line: For probing effective inhibitors of tyrosinase, a combination of computational prediction and enzymatic assay via kinetics was important.Simulation was successful (binding energies for Dock6.3 = -27.22 and AutoDock4.2 = -0.97 kcal/mol), suggesting that PA interacts with LEU73 residue that is predicted commonly by both programs.The present study suggested that the strategy of predicting tyrosinase inhibition based on hydroxyl groups and orientation may prove useful for screening of potential tyrosinase inhibitors.

View Article: PubMed Central - PubMed

Affiliation: College of Biological and Environmental Sciences, Zhejiang Wanli University, Ningbo 315100, China.

ABSTRACT
Tyrosinase inhibition studies are needed due to the medicinal applications such as hyperpigmentation. For probing effective inhibitors of tyrosinase, a combination of computational prediction and enzymatic assay via kinetics was important. We predicted the 3D structure of tyrosinase, used a docking algorithm to simulate binding between tyrosinase and phthalic acid (PA), and studied the reversible inhibition of tyrosinase by PA. PA inhibited tyrosinase in a mixed-type manner with a K(i) = 65.84 ± 1.10 mM. Measurements of intrinsic and ANS-binding fluorescences showed that PA induced changes in the active site structure via indirect binding. Simulation was successful (binding energies for Dock6.3 = -27.22 and AutoDock4.2 = -0.97 kcal/mol), suggesting that PA interacts with LEU73 residue that is predicted commonly by both programs. The present study suggested that the strategy of predicting tyrosinase inhibition based on hydroxyl groups and orientation may prove useful for screening of potential tyrosinase inhibitors.

No MeSH data available.


Related in: MedlinePlus