Fig. 4. Reaction of trastuzumab with the DVP linkers and subsequent analysis. (a) Cysteine bridging of trastuzumab with 7, 8 or 9 resulted in re-bridged mAbs 16, 17 and 18, (b) analysis of conjugate 16, 17 and 18 by SDS-PAGE; lane 1 is non-reducing, lanes 2–5 are reducing; lanes: (M) molecular weight marker, (1) trastuzumab, (2) reduced trastuzumab, (3) 16, (4) 17, (5) 18, and (c) SEC analysis of 18.