Fig. 2. Plasma-membrane-associated GSTs on sperm. (A) Autoradiogram of ¹²⁵I-GSTs purified by GSH affinity chromatography from extracts of the plasma membrane of surface-iodinated sperm in live conditions (lane b). Lane a represents extracts of sperm after removal of the plasma membrane. (B) SDS-PAGE (12%) of GSH affinity-purified GSTs from sperm plasma membrane preparations. Lane a, molecular weight marker; lane b, purified GSTs. (C) Non-reducing SDS-PAGE showing immunoprecipitated proteins from sperm plasma membranes using anti-GST antibodies. (lane a) Preimmune serum; (lane b) anti-GST MuN antibodies; (lane c) anti-GST PiN antibodies; (lane d) migration of GSH affinity-purified sperm plasma membrane GSTs used as a control lane. (D) The RP-HPLC elution profile of sperm plasma membrane GSTs purified by GSH affinity chromatography. Peaks 1 and 2 are GST-Mu, Peak 3 is GST-Pi. (E) Western blots of peaks 1 and 2 represented in D probed with anti-GST M1 antibody (lanes a,b) and anti-GST Pi antibody (lanes c,d), respectively.