The effect of some antineoplastic agents on glutathione S-transferase from human erythrocytes

Figures & data

Table 1.  Purification of glutathione S-transferase from human erythrocytes.

Purification step	Total volume (mL)	Activity (EU/mL)	Total activity (EU)	Protein (µg/mL)	Total protein (µg)	Specific activity (EU/µg)	Yield (%)	Purification fold
Hemolysate	60	0.08	4.80	5.88	352.80	0.014	100	1
Affinity chromatography	8	0.48	3.84	0.03	0.24	16.000	80	1143

Table 2.  IC₅₀, K_i values and inhibition types for paclitaxel, cyclophosphamide, and gemcitabine toward human erythrocyte GST in fixed CDNB.

Inhibitors	IC50 values (mM)	Ki constants (mM)	Avarage Kiconstants (mM)	Inhibition Type
Paclitaxel	0.23	0.185	0.182 ± 0.028	Non-competitive
		0.153
		0.208
Cyclophosphamide	5.57	7.23	6.97 ± 0.49	Non-competitive
		7.28
		6.41
Gemcitabine	6.35	6.40	6.71 ± 0.31	Non-competitive
		6.72
		7.02

Table 3.  IC₅₀, K_i values and inhibition types for paclitaxel, cyclophosphamide, and gemcitabine toward human erythrocyte GST in fixed GSH.

Inhibitors	IC50 values (mM)	Ki constants (mM)	Avarage Kiconstants (mM)	Inhibition type
Paclitaxel	0.23	0.238	0.162 ± 0.068	Non-competitive
		0.143
		0.106
Cyclophosphamide	5.57	16.24	10.50 ± 5.43	Non-competitive
		9.83
		5.43
Gemcitabine	6.35	7.32	7.93 ± 0.56	Non-competitive
		8.04
		8.42

Figure  1.  SDS-PAGE of pure human erythrocytes GST. Lane 1, Molecular mass standarts; lane 2, The enzyme purified from human erythrocytes by Glutathione-Agarose affinity column.