Dear all, I work with collagen based films and I need to understand why collagen swelling happens at acidic pH. I thought that the protein must be far from its isoelectric point in order to maximise the swelling, but I found different papers giving different values for the isoelectric point of collagen. At this point I am thinking that the swelling happens at acidic pH for another mechanism. Can any of you help me with this? Maybe suggesting me some papers.
Thank you very much for your help!
Hi Annalisa,
look at this source, I think it's helpful.
figure 32(page 149) explains that in acidic condition, negative side chains of collagen get discharged by hydrogen ions and that causes the vertical swelling.
"Advances in Protein Chemistry, Volume 7"
https://books.google.com/books?id=qKBaL0K6ygAC&pg=PA147&lpg=PA147&dq=swelling+behavior+of+collagen+in+acidic+ph&source=bl&ots=gXQ5tERGMV&sig=PWu2eaeZCd6I6j0d63wjZOIZxoM&hl=en&sa=X&ved=0ahUKEwiPzrjFs7DQAhVk5YMKHQM7A-8Q6AEIMjAD#v=onepage&q=swelling%20behavior%20of%20collagen%20in%20acidic%20ph&f=false
hope that helps.
Dear Nasim and Richard,
thank you very much for your help. The book suggested looks very helpful.