Protein denaturation by interaction with alcohols

Alcohols disrupt hydrogen bonds found in secondary, tertiary, and quaternary structures. They form new hydrogen bonds between them and the amino acids (Figure 1). This leads to the exposure of hydrophobic amino acids to the surface as they are more soluble in organic solvents such as alcohols and subsequently a change in protein conformation that denatures the protein.

Figure 1. Disruption of Hydrogen bond by addition of ethanol.

This happens for instance when using 70% ethanol to disinfect our skin before getting an injection. The alcohol denatures proteins of any bacteria present on the skin, making them non-functional and subsequently avoiding a possible infection in the injection site.