Annexin Lectins: Ca²⁺-Dependent Heparin-Binding Activity, Phosphatidylserine-Binding Activity, and Anticoagulant...

Among numerous heparin-binding proteins identified in animal tissues and body fluids, annexins are unique because their activies depend on their Ca²⁺ binding. Annexins are known to have other Ca²⁺-dependent activities. For example, they bind to phosphatidylserine in the plasma membrane, and some of them exhibit potent anticoagulant activity. This chapter describes three protocols that measure the Ca²⁺-dependent activities using recombinant annexins: solid-phase heparin-binding assay using bovine serum albumin-conjugated heparin, solid-phase phosphatidylserine-binding assay, and plasma coagulation inhibition assay.