Cholesterol esters are formed by esterifying cholesterol with fatty acids. Which molecule serves as that fatty acid donor?

Cholesterol esters are formed by esterifying cholesterol with fatty acids. Which molecule serves as that fatty acid donor?

• A. Protein
• B. Triglyceride
• C. Fatty acid
• D. Digitonin

Answer: (C)

Cholesterol esters form when a fatty acyl group is attached to the hydroxyl on cholesterol, creating an ester bond. The molecule that donates that fatty acyl piece is a fatty acid, typically supplied in cells as a fatty acyl-CoA that the enzyme ACAT uses to transfer the fatty acid to cholesterol. So the fatty acid is the donor of the acyl group in this reaction. Protein isn’t involved in donating an acyl group here, digitonin serves no role in this esterification, and while triglycerides contain fatty acids, they are not the direct acyl donor in the cholesterol esterification step.

Cholesterol esters form when a fatty acyl group is attached to the hydroxyl on cholesterol, creating an ester bond. The molecule that donates that fatty acyl piece is a fatty acid, typically supplied in cells as a fatty acyl-CoA that the enzyme ACAT uses to transfer the fatty acid to cholesterol. So the fatty acid is the donor of the acyl group in this reaction.

Protein isn’t involved in donating an acyl group here, digitonin serves no role in this esterification, and while triglycerides contain fatty acids, they are not the direct acyl donor in the cholesterol esterification step.