Inhibitory effects of Cefazolin and Cefodizime on the activity of mushroom tyrosinase

Figures & data

Figure 1.  Chemical structure of Cefazolin (a) and Cefodizime (b).

Figure 2.  Progress curves for the inhibition of monophenolase activity of mushroom tyosinase by Cefazolin. (a) The concentrations of Cefazolin for curves 1–6 were 0, 2.0, 4.0, 6.0, 8.0 and 10.0 mM, respectively. (b) Relationship of the steady-state rate with the concentrations of Cefazolin. (c) Relationship of the lag time with the concentrations of Cefazolin.

Figure 3.  Progress curves for the inhibition of monophenolase activity of mushroom tyosinase by Cefodizime. (a) The concentrations of Cefodizime for curves 1–6 were 0, 0.1, 0.2, 0.3, 0.4 and 0.5 mM, respectively. (b) Relationship of the steady-state rate with the concentrations of Cefodizime. (c) Relationship of the lag time with the concentrations of Cefodizime.

Figure 4.  Effects of Cefazolin (a) and Cefodizime (b) on the diphenolase activity of mushroom tyrosinase.

Figure 5.  Determination of the inhibitory mechanism of Cefazolin on mushroom tyrosinase. The concentrations of Cefazolin for curves 1–6 were 0, 0.04, 0.08, 0.12, 0.16and 0.2 mM, respectively.

Figure 6.  Determination of the inhibitory type and inhibition constants of Cefazolin on mushroom tyrosinase. (a) Lineweaver-Burk plots of the diphenolase activity of mushroom tyrosinase inhibited by cefazolin. The concentrations of Cefazolin for curves 1–6 were 0, 0.04, 0.08, 0.12, 0.16 and 0.20 mM, respectively. (b) The plot of K_m app. verus the concentration of Cefazolin to determine the inhibition constant.

Table I.  Inhibition constants of Cefodizime and Cefazolin with mushroom tyrosinase.

Constants		Cefazolin	Cefodizime
IC50	Monophenolase	7.0 mM	0.13 mM
	Diphenolase	0.21 mM	0.02 mM
	Inhibition	Reversible	Reversible
	Inhibition type	Competitive	Mixed
	KI	0.11 mM	12.9 μM
	KIS		51.1 μM

Figure 7.  Determination of the inhibitory type and inhibition constants of cefodizime on mushroom tyrosinase. (a) Lineweaver-Burk plots of the diphenolase activity of mushroom tyrosinase inhibited by cefodizime. The concentrations of cefodizime for curves 1–6 were 0, 0.005, 0.01, 0.015, 0.02 and 0.025 mM respectively. (b) The plot of the slope versus the concentration of cefodizime. (c) The plot of the intercept versus the concentration of cefodizime.