As a result of talking to technical service from BMB:

Using Factor Xa from BMB, re suspend in Milli-Q water:

Stable ~1 week in solution, 1mg/ml at 4°. Don't freeze.

Lyophilized, stable for a couple of months -20°C

Standard Cleavage:

100mM NaCl

50mM Tris-HCl

1mM CaCl2

Protein at ~1mg/ml

Add Factor Xa at 0.5% to 10%

Incubate 4°C to 25°C, for 2 to 18 hours

Difficult Cleavage:

Can add ß-Mercaptoethanol to reduce

Can add Urea up to 1 molar to denature, allow better access of Factor Xa to cleavage site

Can add up to 10% Acetonitrile to denature as well.