3.4.21.27	Ca2+	-	683169	
3.4.21.27	Ca2+	5 mM used in assay conditions	752757, 753069	
3.4.21.27	Ca2+	factor XIa activates factor IX upon the addition of Ca2+	718042	
3.4.21.27	Ca2+	required for proteolytic activity	683167	
3.4.21.27	Ca2+	substrate factor IX: Ca2+ activates	36532, 36534, 36536	
3.4.21.27	Zn2+	in the presence of zinc ions, kininogen is required for optimal FXI binding to GP1b on activated platelets in suspension, enhancing the binding stoichiometry by approximately 2fold	707856