1. FseI is one of the least stable restriction enzymes when stored at -20°C. We recommend storage at -70°C if it is to be stored for longer than 30 days. 2. FseI is strongly inhibited by certain salts, including NaCl or ammonium acetate. If you perform alcohol precipitation before digestions with FseI, use sodium acetate (or potassium acetate) as the salt in the precipitation.