IGFBP-4 Human Recombinant amino acids Asp22- Glu258, produced in HEK293 cells and fused with a polyhistidine tag at the C-terminus. IGFBP4 predicted Mw is 27kDa and on SDS-PAGE appears as a 32kDa band under denaturing conditions. IGFBP4 is purified by proprietary chromatographic techniques.