Lyophilized powder may be stored at 4 degree C. Stable for 12 months at 4 degree C. Reconstitute with sterile ddH2O. Aliquot to avoid repeated freezing and thawing. Store at 4 degree C. Reconstituted product is stable for 12 months at 4 degree C. Freezing R-Phycoerythrin (PE) conjugates will result in a substantial loss of activity. PE conjugates are sensitive to light.