We recommend using sterile or RODI water for the initial reconstitution of the lyophilized protein. For details, refer to the products’ package insert. After dissolution, dilute the enzyme to the appropriate volume for use in your application. If you want to use a solution other than water to reconstitute the lyophilized protein, avoid using solutions that contain chemicals or chelating agents that can bind to metal cations (e.g., zinc, calcium). These cations are critical for maintaining the enzyme activity of bacterial collagenase or neutral protease (e.g., BP Protease, Dispase, Thermolysin, clostripain, C. histolyticum neutral protease). Any material that contains a metal chelating agent (e.g., EGTA, EDTA) should never be used. The phosphate in phosphate buffered saline will remove calcium from collagenase if stored for long periods of time so it is strongly recommended not to store bacterial collagenase or protease in this solution. If using a culture media such as CMRL 1066 or RPMI 1640, avoid serum as it will inhibit protease activity.