Not available outside of the UK & Ireland.

Application

Fusion proteins are commonly expressed with a factor Xa cleavable Ile-Glu (or Asp)-Gly-Arg-↓-X sequence. Typically 1 mg of fusion protein can be incubated with 10 µg of factor Xa for 2.5 hours at 37 °C.

Biochem/physiol Actions

Factor Xa catalyzes the hydrolysis of the Arg-Thr and then Arg-Ile bonds in prothrombin to yield active thrombin.The fairly strict recognition sequence is Ile-Glu (or Asp)-Gly-Arg-↓-X.It may sometimes cleave at other basic residues, depending on the conformation of the target protein. Factor Xa will not cleave if a proline residue follows the arginine of the recognition sequence.pH Optimum: 7.6-8.0Temperature Optimum: 37 °C

Physical properties

Factor Xa is a serine endoproteinase and a member of the S1 peptidase family. Factor Xa plays a critical role in the coagulation cascade by catalyzing the proteolytic conversion of prothrombin to active thrombin. Factor Xa′s prothrombin conversion activity is greatly enhanced in vivo when complexed with factor V, calcium ions and phospholipids on the activated platelet surface.The zymogen form, Factor X, is activated in vivo by two different pathways. The intrinsic pathway utilizes a catalytic complex composed of factor IXa, factor VIII, phospholipids and calcium ions. The extrinsic pathway utilizes a complex of factor VII and tissue factor. The factor X zymogen is a 55 KDa glycoprotein with a light and heavy chain joined by a single disulfide.

Unit Definition

One unit of activated Factor X will liberate 1.0 µmole of p-nitroanilide from N-benzoyl-L-isoleucyl-L-glutamyl-L-glycyl-L-arginine-p-nitroaniline per minute at pH 8.3 at 37 °C.