In vitro effects of some drugs on human red blood cell glucose-6-phosphate dehydrogenase enzyme activity

Figures & data

Figure 1 SDS-polyacrylamide gel electrophoresis of G-6PD purified by affinity gel. Lane 1 and 2 are standard albumin (66.000) and lanes 3–4 are G-6PD.

Figure 2 Activity % -[Omeprazole] regression analysis graphs for human erythrocytes G-6PD in the presence of 5 different omeprazole concentrations.

Figure 3 Activity % -[Morphine Sulphate] regression analysis graphs for human erythrocytes G-6PD in the presence of 5 different morphine sulphate concentrations.

Figure 4 Activity % -[Vankomycin] regression analysis graphs for human erythrocytes G-6PD in the presence of 5 different vankomycin concentrations.

Figure 5 Activity % -[Ketamine] regression analysis graphs for human erythrocytes G-6PD in the presence of 5 different ketamine concentrations.

Figure 6 Activity % -[Remifentanyl] regression analysis graphs for human erythrocytes G-6PD in the presence of 5 different remifentanyl concentrations.

Figure 7 Lineweaver–Burk graphs for G-6PD in presence of three constant omeprazole and five different substrate concentrations.

Figure 8 Lineweaver–Burk graphs for G-6PD in presence of three constant morphine sulphate concentrations and five different substrate concentrations.

Figure 9 Lineweaver–Burk graphs for G-6PD in presence of three constant vankomycin concentrations and five different substrate concentrations.

Table I.  Purification scheme of glucose 6-phosphate dehydrogenase from human erythrocytes.

Purification step	Activity (EU/ml)	Total volume (ml)	Protein (mg/ml)	Total protein (mg)	Total activity (EU)	Specific activity (EU/mg)	Yield (%)	Purification factor
Haemolysate	1.2	80	42.2	3376	96	0.028	100	1
Ammonium sulfate precipitation (35–65)%	1.3	25	0.93	23.25	32.5	1.39	33.85	49.64
2′,5′- ADP sepharose 4B affinity chromatography	3.4	8	0.054	0.432	27.2	62.96	28.33	2248

Table II.  K_i and I₅₀ values obtained from Lineweaver–Burk graphs for G-6PD in the presence of three fixed inhibitors and five substrate concentrations for omeprazole, morphine sulphate, and vankomycin. I₅₀ values for remifentanyl and ketamine.

Inhibitor	[I] (mM)	Ki values (mM)	Mean Ki values (mM)	I50 value (mM)	Inhibition type
Omeprazole	1,200	9.002	8.22 ± 2.055	3.24	Noncompetitive
	3.474	8.330
	5.790	7.330
Morphine	6.600	27.73	25.93 ± 6.482	43.58	Noncompetitive
	13.20	23.48
	26.40	26.58
Vankomycin	0.688	2.73	2.71 ± 0.677	0.903	Noncompetitive
	1.376	2.81
	2.752	2.59
Ketamine	–	–	–	64.16	–
Remifentanyl	–	–	–	97.6	–