11/24/23

Dear Amit,

Glycoproteins will react with biuret assay reagents to give a bluish color, so you can use it to measure the protein moiety of glycoproteins. The biuret assay is easy to perform and works; however, it is less sensitive than other protein assay techniques. A better assay is the DC Method. This is a modification of the older Lowry method, but it does work well and is sensitive. The color produced is formed in part by Cu reacting w/ peptide bonds, so it will detect glycoproteins. See https://www.bio-rad.com/webroot/web/pdf/lsr/literature/LIT448.pdf.

Another method is the Bicinchoninic Acid (BCA) assay. See https://en.wikipedia.org/wiki/Bicinchoninic_acid_assay.

This is also easy to do and will work w/ glycoproteins. It is also more sensitive than both the biuret and DC protein assays.

The carbohydrate (CHO) portion of glycoproteins can be detected by general CHO assay procedures, e.g., the Phenol-H2SO4 method (Dubois et al., Anal. Chem. 28:350-356). This is an OLD method, but it is still used. It is easy to do and very sensitive.

Please note that ALL of the above methods are destructive, i.e., the glycoprotein is destroyed be the reagents used in the assays. A non-destructive method for detecting the protein moiety of a glycoprotein is to measure its absorbance at 280 nm.

I hope this information helps you. Good luck w/ your research.

Bill Colonna

Dept. Food Science & Human Nutrition

Iowa State University, Ames, Iowa USA

[email protected]