AAT Bioquest

How do acids and bases denature a protein?

Posted June 22, 2020


Acids and bases can significantly change the environmental pH of proteins, which disrupts the salt bridges and hydrogen bonding formed between the side chains, leading to denaturation. Increasing the pH by adding bases converts the pronated -NH3+ ion to a neutral -NH2 group?while decreasing the pH by adding acids converts the -COO- ion to -COOH group. These changes prohibit the ionic attraction between the side chains, i.e. salt bridges, resulting in the unfolding of proteins. Meanwhile, the change of pronation status also affects the participation of amino acid residues in forming hydrogen bonds, causing the disruption of protein’s 3D structure. Acid-induced denaturation often occurs between pH 2 and 5, and base-induced unfolding usually requires pH 10 or higher.

Additional resources

Amplite™ Fluorimetric Fluorescamine Protein Quantitation Kit *Blue Fluorescence*

Amplite™ Rapid Colorimetric Total Protein Thiol Quantitation Assay Kit

Branden, C. I., & Tooze, J. (2012). Introduction to protein structure. Garland Science.

Tanford, C. (1968). Protein denaturation. In Advances in protein chemistry (Vol. 23, pp. 121-282). Academic press.