Hi
I tested the stability of catalase during freeze-drying.
I have found through FT-IR that the amide 2 of catalase has damaged during freeze-drying.
The catalase activity assay result also showed about 50% less than the native catalase.
I want to know the relationship between catalase activity and amide 2.
The amide II feature is sensitive to the tertiary structure of the protein. If freeze-drying the protein causes some of the protein to be denatured, this will be reflected as a change in the amide II band. Denaturation of the protein is responsible for the loss of catalytic activity.
Thank you your answer.
Thank you for your reply. Do you know how to accurately detect the cause of loss of catalytic activity by detecting the amino acid damage of the catalase active sites, His and Asn?
To get to that level of detail would probably require 2-D protein NMR with peak assignments.
In the case of freeze-drying, the loss of activity is due to dehydration of the protein, probably leading to denaturation of the tertiary structure and also possibly aggregation, rather than chemical damage to individual amino acid residues. Proteins can be protected from denaturation during freeze-drying, in some cases, by including a protective excipient such as sucrose or trehalose.
If freeze-drying is not necessary for your work, avoid it.
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