This product is supplied in the form of aqueous suspension which is quite stable when stored refrigerated at 2 - 8 °C. Avoid freezing the solution as the thawing process will cause a decline in activity. This item is not assigned an expiration date, but is warrantied for 1 year from the date of shipment. A lyophilized Catalase product, C40, is assigned a retest date of 3 years from the date of release. See the links below for additional information.
Product Data Sheet:
https://www.sigmaaldrich.com/deepweb/assets/sigmaaldrich/product/documents/338/431/c100pis.pdf
Product Dating Information:
https://www.sigmaaldrich.com/deepweb/assets/sigmaaldrich/marketing/global/documents/190/408/product-dating-information-ms.pdf
C40 Catalase, lyophilized powder, specification sheet:
https://www.sigmaaldrich.com/specification-sheets/253/868/C40-BULK__________SIGMA____.pdf