National University of Singapore
Question
Asked 2 May 2024
How to analyze the percentages of covalently-bound and noncovalently-bound polyphenols during protein extraction?
I extracted protein from a roasted food sample using alkaline extraction followed by acid precipitation. Polyphenols were always coextracted since they were covalently bound with proteins during roasting and the formation of covalent bonds were irreversible. How can I know how abundant covalently-bound and noncovalently-bound polyphenols are in my protein extracts? I would greatly appreciate it if you could provide any suggestion or guidance.
All Answers (2)
If I use methanol and acetic acid to extract polyphenol and wash protein extracts. Are the polyphenols in washing solution all non-covalently bound? And are the unremoved polyphenols in protein extracts covalently-bound? Can I detect the TPC values in both washing solution and protein extracts to indicate the abundance of noncovalently bound and covalently-bound polyphenols?
neowistra GmbH
To proof that a small molecule is covalently bound to a polymer is very challenging. I was in similar situation when I tried to bind polyphenols covalently to chitosan. Generally, the polyphenols in your washing solution were either non-covalently bound or the covalent bond was cleaved during washing. The unremoved polyphenols are not necessarily bound covalently, as non-covalent interactions can still be too strong.
You could try to depolymerise your protein (e.g. by enzymatic hydrolysis) and then analyse the fragments (e.g. by LC-MS). If you find a fragment with the polyphenol bound covalently, you have a proof.
1 Recommendation
Similar questions and discussions
Related Publications
Long-range non-covalent interactions play a key role in the chemistry of natural polyphenols. We have previously proposed a description of supramolecular polyphenol complexes by the B3P86 density functional coupled with some corrections for dispersion. We couple here the B3P86 functional with the D3 correction for dispersion, assessing systematical...
Normally the olive oil quality is assessed by chemical analysis according to international standards. These norms define chemical and organoleptic markers, and depending on the markers, the olive oil can be labelled as lampante, virgin, or extra virgin olive oil (EVOO), the last being an indicator of top quality. The polyphenol content is related t...
Typescript (photocopy). Thesis (M.S.)--Oregon State University, 1996. Includes bibliographical references (leaves 70-74).