Lyophilized powder may be stored at 4 degree C. Stable for 12 months at 4 degree C. Reconstitute by adding sodium-calcium chloride to a concentration of >0.1%. Aliquot and store at 4 degree C for 1 week. For maximum recovery of product, centrifuge the original vial after thawing and prior to removing the cap. Further dilutions can be made in assay buffer.