In vitro inhibition effects of some coumarin derivatives on human erythrocytes glucose-6-phosphate dehydrogenase activities

Figures & data

Scheme 1. Structure of coumarin.

Figure 1. SDS-PAGE of purified human erythrocyte G6PD. The enzyme was electrophoresed at pH: 8.3 on a 12% polyacrylamide gel and stained with Coomassie Brilliant Blue R-250. Lanes: 1, molecular weight standards (β-galactosidase, 116 kDa; bovine serum albumin, 66.2 kDa; egg albumin, 45 kDa; lactate dehydrogenase, 35 kDa; Rease Bsp981 (Escherichia coli), 25 kDa; β-lactoglobulin, 18.4 kDa; Lysozyme, 14.4 kDa; 2, purified human erythrocyte G6PD).

Table 1. Kinetic parameters of human erythrocyte glucose-6-phosphate dehydrogenase.

Substrate	Km (mM)	Vmax (U/mg)
G6P	0.22	1.94
NADP	0.14	2.76

Figure 2. Activity % curve of G6PD in different OPC, MPC and PPC concentrations.

Figure 3. Lineweaver–Burk graphs in five different substrate (G6P) concentrations sand in two different OPC, MPC and PPC concentrations for determination of K_i.

Table 2. Chemical structures of the synthesized coumarins.

Structure		Abbreviation
		OPC
		MPC
		PPC

Table 3. Inhibition type, K_i and I₅₀ values obtained from regression analysis graphs for G6PD in the presence of coumarin derivatives.

Coumarin	Inhibition type	Ki (mM)	IC50 (mM)
OPC	Noncompetitive	1.37	0.305
MPC	Mixed	0.734	0.769
		0.269
PPC	Uncompetitive	0.835	0.790