Question

Scientists observe that when proteins are extracted into detergent micelles, they sometimes lose their ability to function. For example, a channel may not be able to pass ions or an enzyme may not be able to catalyze reactions after extraction. Explain how the shape of the detergent, the length of the detergent fatty acyl chain or the polarity/charge on the detergent headgroup may be the reasons for the lack of protein’s functionality.

Answer 1

When this occurs to proteins it means the tertiary structure was disrupted by the detergent. Remember the tertiary structure is the complex and specific way of folding that gives the protein the 3D configuration and the functionality to its domains. This structure forms by chemical interactions like the disulfide bonds, hydrophobic interactions and the hydrophilic interaction with the acquous medium.

Detergents work by having both hydrophobic and hydrophilic parts, the fatty acid tail and a ionic group in the head, the ionic group interacts with water while the hydrophobic fatty acid tail interacts with lipids and forms the micelles. The chemical interactions made by the detergents can be very strong, strong enough to start interacting with the hydrophobic groups in proteins, thus leading to disruption of their tertiary structure, then they lose their functionality.