How can factor Xa be inactivated?
The best way is 2 uM dansyl-glu-gly-arg-chloromethyl ketone. This compound irreversibly inactivates the enzyme. We get it from Calbiochem, #251700, but there may be other suppliers. We add to a final concentration of 2 uM, then incubate at least 1 min. at room temperature. It reacts with the active site histidine, so it could conceivably react with other sites on the protein of interest, but this is unlikely at the low concentration used. The protease inhibitor chymostatin (60 ug/ml) also works.
