When insulin becomes denatured

Protein denaturation is the unfolding of the secondary or tertiary structures (1). For example, heat can denature proteins in eggs by disrupting hydrogen bonds and non-polar hydrophobic interactions and as a result the egg proteins coagulate during cooking (1). Alcohol, like heat, can also disrupt hydrogen bonds, and acids, bases and heavy metal salts denature proteins by disrupting salt bridges (1).

What are biochemical consequences of denaturation of insulin?

In the body, protein denaturation can affect processes biochemically. Native insulin, for example, in the presence of increased, urea may be denatured because of changes in pH or, in the presence of a thiol catalyst, may be denatured due to isomerization (2). The insulin, thus, is unable to properly cause cells to take up glucose as it should (2).

Reference List
1. Ophardt CE. 2003. “Denaturation of Proteins.” Virtual Chembook. Available at: http://www.elmhurst.edu/~chm/vchembook/568denaturation.html
2. Jiang C, Jui-Yoa Chang. 2005. Unfolding and breakdown of insulin in the presence of endogenous thiols. FEBS Letters, 579;18. Available at: http://www.febsletters.org/article/S0014-5793(05)00720-9/abstract.
3. Chemistry and Biochemistry Department of Ohio University [Web page]. “Proteins.” Available at: http://dwb4.unl.edu/Chem/CHEM869K/CHEM869KLinks/main.chem.ohiou.edu/~wathen/chem302/protein.html