Total Cholesterol and Cholesteryl Ester Assay Kit

Cholesterol is an essential component of cell membranes and a critical precursor for the synthesis of bile acids and various hormones, playing a vital role in maintaining normal physiological functions. It exists in two forms: cholesterol esters, bound to fatty acids, and a smaller fraction of unesterified (free) cholesterol. Together, these constitute total cholesterol. Cholesterol concentration serves as a key indicator of lipid metabolism status and is closely associated with the risk of cardiovascular and cerebrovascular diseases, such as liver disease, nephrotic syndrome, and atherosclerosis.

This kit is designed to detect total cholesterol, free cholesterol, and cholesterol ester concentrations in samples such as cells, tissues, and serum. The detection principle is that cholesterol esters can be hydrolyzed into free cholesterol by cholesterol esterase. Subsequently, all free cholesterol is oxidized by cholesterol oxidase to produce hydrogen peroxide. In the presence of horseradish peroxidase, hydrogen peroxide reacts with the Amplex Red probe to form the red-fluorescent product resorufin. Total cholesterol content is quantified by detecting the fluorescence or absorbance of resorufin. Free cholesterol can be specifically measured by omitting cholesterol esterase in the reaction. Cholesterol ester content is then calculated as the difference between total cholesterol and free cholesterol.

Figure 1. Typical standard curve and assay data. (A) The reference standard curve, (B) Assessment of cholesteryl ester and free cholesterol levels in mouse serum.