Low-density lipoproteins (LDL) are the major carriers of cholesterol in humans, responsible for
supplying cholesterol to tissues with the highest sterol demands. Low-density lipoprotein cholesterol
(LDL-C) concentrations positively correlate with the incidence of coronary heart disease and a reduction of
LDL-C decreases the risk of coronary. Therefore, accurate and precise measurements of patients’ LDL-C
concentrations are necessary to appropriately identify individuals with atherosclerosis, coronary heart
disease and hypertension.
Cholesterol of chylomicrons (CM), very-low-density lipoproteins (VLDL), high-density lipoproteins
(HDL) is specifically dissociated by one surfactant, but LDL-C is not dissociated by the surfactant.
Cholesterol ester and cholesterol oxidase can catalyze the hydrolysis of dissociated cholesterol to produce
H2O2, which cannot form colored compounds without chromogenic agents. Cholesterol is specifically
dissociated by another surfactant from undissociated LDL. Esterase can catalyze the hydrolysis of
cholesterol ester to produce free cholesterol (FC) and free fatty acid (FFA), thus transforming cholesterol
ester into FC; Furthermore, cholesterol oxidase can catalyze FC to form Δ4-cholesterone and H2O2;
Finally, peroxidase can catalyze the oxidation of 4-aminoantipyrine and phenyl amines by H2O2 to form
purple quinones. It has a characteristic absorption peak at 546 nm, and its color depth is directly
proportional to cholesterol content.
BC5330 – Page 1 / 4
