I bought xanthine oxidase enzyme in ammonium sulfate suspension from Sigma Aldrich. Do I need to remove the suspension first before doing the xanthine oxidase inhibitory assay? If I do not remove it, would it affects my results later on?
Hi there,
You need to recover the protein precipitate from your suspension by centrifugation and then resuspend the pellet in the suitable buffer to generate your protein stock. Activity assay has to be run using this latter stock.
https://www.sigmaaldrich.com/technical-documents/articles/biology/ammonium-sulfate-suspensions.html
working with enzymes supplied in ammonium sulfate suspensions
It is not always necessary to centrifuge the suspension. If the enzyme is going to be highly diluted anyway into an enzyme reaction, and if the amount of ammonium sulfate does not interfere with the reaction or detection of the product, then you can just make sure the suspension is thoroughly (but gently) mixed and take out the amount you need. Store the suspension at 4oC, not in the freezer.
Ammonium sulfate suspensions typically contain about 3 M ammonium sulfate.
Thank you Dr Dominique Liger, Dr Mushtaq Ahmad and Dr Adam B Shapiro for the answers.
- Badges
- Science topic
- Similar topics
- Biological Science
- Biochemistry
- Enzymology
- Enzymes