Purification of glutathione S-transferase isoenzymes from tumour and nontumour human stomach and inhibitory effects of some heavy metals on enzymes activities

Figures & data

Figure 1.  Lane (1) human tumour gastric GST. Lane (2) human nontumour gastric GST. Lane (3) standard proteins (E. coli β-galactosidase (116 kDa)), rabbit phosphorylase B (97.4 kDa), bovine serum albumin (66 kDa), chicken ovalbumin (45 kDa) and bovine carbonic anhydrase (29 kDa) SDS-PAGE analysis of purified.

Table 1.  Summary of purification procedure for tumour human gastric GST.

Purification steps	Activity (EU/mL)	Total volume (mL)	Protein (mg/mL)	Total protein (mg)	Total activity	Specific activity (EU/mg)	Yield %	Purification fold
Homogenate	0.094	23	14.43	331.89	2.162	0.0065	100.0	1.0
Dialyzed enzyme after affinity chromatography	0.241	7	0.012	0.084	1.687	20.08	78.03	3089.23

Table 2.  Summary of purification procedure for nontumour human gastric GST.

Purification steps	Activity (EU/mL)	Total volume (mL)	Protein (mg/mL)	Total protein (mg)	Total activity	Specific activity (EU/mg)	Yield %	Purification fold
Homogenate	0.088	20	18.23	364.6	1.76	0.0048	100.0	1.0
Dialyzed enzyme after affinity chromatography	0.148	6	0.026	0.156	0.888	5.69	50.45	1185.4

Table 3.  K_i values and inhibition types for two metal ions of tumour and nontumour GST.

Type of metals	For tumour tissueAverage values of Ki (mM)	Type of inhibition	For nontumour tissue average values of Ki (mM)	Type of inhibition
Zn^2+	Not Significant	–	Not Significant	–
Cu^2+	Not Significant	–	Not Significant	–
Fe^2+	Not Significant	–	Not Significant	–
Cd^2+	2.01	Uncompetitive	7.38	Uncompetitive
Pb^2+	Not Significant	–	Not Significant	–
Cr^2+	Not Significant	–	Not Significant	–
Al^3+	Not Significant -	–	Not Significant	–
Ni^2+	Not Significant	–	Not Significant	–
Mn^2+	Not Significant	–	Not Significant	–
Mg^2+	48.096	Uncompetitive	49.2	Uncompetitive