Sequence variants of the ATIII binding pentasaccharides. A: 3S, 6S and 3S6S are the pentasaccharides with sulfation at the critical 3-O, 6-O and both positions, respectively. B: Gel mobility shift analysis of labeled pentasaccharides for their ability to bind to ATIII. In each lane, ~ 100, 000 cpm radiolabeled pentasaccharide was incubated with or without ATIII at room temperature for 20 minutes and the complexes were resolved under native conditions.