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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

Secondary replots. (a) Plot of Slope versus [PA]. All data were collected from Lineweaver-Burk plots. The replot was plotted based on (2). (b) Plot of Y-intercept versus [PA]. The replot was plotted based on (3).
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fig4: Secondary replots. (a) Plot of Slope versus [PA]. All data were collected from Lineweaver-Burk plots. The replot was plotted based on (2). (b) Plot of Y-intercept versus [PA]. The replot was plotted based on (3).

Mentions: We adapted Lineweaver-Burk plot analysis to elucidate inhibition type and mechanism of PA on tyrosinase. The results showed changes in both the apparent Vmax and the Km, indicating that PA induced a mixed type of inhibition (Figure 3). The secondary replots of Slope versus (PA) and Y-intercept versus (PA) were linearly fitted (Figures 4(a) and 4(b)), showing that PA has a single inhibition site or a single class of inhibition site on tyrosinase. Using (1)–(3), the α-value was calculated to be 9.05 ± 1.4 (n = 2), and the Ki was 65.84 ± 1.10 mM (n = 2).


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

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

Secondary replots. (a) Plot of Slope versus [PA]. All data were collected from Lineweaver-Burk plots. The replot was plotted based on (2). (b) Plot of Y-intercept versus [PA]. The replot was plotted based on (3).
© Copyright Policy - open-access
Related In: Results  -  Collection

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

fig4: Secondary replots. (a) Plot of Slope versus [PA]. All data were collected from Lineweaver-Burk plots. The replot was plotted based on (2). (b) Plot of Y-intercept versus [PA]. The replot was plotted based on (3).
Mentions: We adapted Lineweaver-Burk plot analysis to elucidate inhibition type and mechanism of PA on tyrosinase. The results showed changes in both the apparent Vmax and the Km, indicating that PA induced a mixed type of inhibition (Figure 3). The secondary replots of Slope versus (PA) and Y-intercept versus (PA) were linearly fitted (Figures 4(a) and 4(b)), showing that PA has a single inhibition site or a single class of inhibition site on tyrosinase. Using (1)–(3), the α-value was calculated to be 9.05 ± 1.4 (n = 2), and the Ki was 65.84 ± 1.10 mM (n = 2).

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