Unlike USP porcine heparin, bovine intestinal heparin (BIH) has a low anticoagulant activity. Treatment with 6-OST-1, -3, and/or 3-OST-1 afforded two remodeled heparins that met USP heparin activity and Mw specifications. We explored the pharmacodynamics and pharmacokinetics in a rabbit model. We conclude that a modest increase in the content of 3-O-sulfo groups in BIH increases the number of antithrombin III binding sites, making remodeled BIH behave similarly to pharmaceutical heparin.