1. Factor Xa recognizes sites Ile-Glu-Gly-Arg^-X.

2. Add 5-100 units Factor Xa per mg of protein. Digest 1 mg of protein in 1-4 ml of reaction buffer (20 mM Tris-HCl pH 6.5, 50 mM NaCl, 1 mM CaCl₂).

Protein can be either in solution or bound on beads. The amount of Factor Xa needed should be determined in a small scale trial.

3. Incubate at room temperature for 3-18 hours.

4. Factor Xa can be removed from sample protein by gel-filtration or Factor Xa removal resin.

See also Cleavage --- thrombin.