A rapid and simple method for the determination of Lecithin cholesterol Acyltransferase (LCAT) activity in serum was investigated by using immobilized cholesterol oxidase (COD)-peroxidase (POD)-voltammetry system and by applying to flow injection analygis.
In this system, suitable protdn donor (Resorcinol) was oxidized by immobilized POD and by hydrogen peroxide (H2O2) which had been produced from the reaction of free cholesterol and immobilized COD.Then, oxidized proton donor was reduced voltammetrically and the reduced current was proportional to the amount of free cholesterol as well as H
2O
2.
Detection limit of free cholesterol in serum was 5 ng and calibration curve was inear to 200ng of free cholesterol.This system was much more sensitive than conventional colorimetry using phenol 4-aminoantipyrine-COD-POD system.Accordingly, it was realized that incubation time could be shorten from 120 minutes of the conventional method to 30 minutes and sample volume could be decreased from 500μl to 50μl.
Furthermore, this system was free from influence of other compounds in serum at the voltage of-150mV vs.Ag-AgCl and was comparatively simple to use.
The correlation coefficient of the present method to colorimetry was 0.911 (n=20).
Therefore, the present method was found to be suitable for the routine assays of serum LCAT activity in the clinical laboratories.
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