A, Agarose gel (1.2% w/v) electrophoresis for RT–PCR products of CdGSTP1-1 using the specified primers and camel liver cDNA. Left, DNA ladder; Right, RT–PCR products; B, SDS-PAGE analysis of purified CdGSTP1-1 enzyme. Lane 1, molecular weight markers; Lane 2, crude extract of E. coli BL21(DE3) uninduced; Lane 3 and 4, crude extract of E. coli BL21(DE3) induced with 1 mM IPTG after 2 and 4 h.