Application of Chromogenic Substrate DAOS in Detection of low Density Lipoprotein

The chromogenic substrate DAOS is a sodium sulfonate derivative containing aniline group, with CAS No 83777-30-4, which belongs to a very sensitive chromogenic reagent and is widely used in various biochemical reagents in biochemical kit, here is a brief introduction to its application in the low-density lipoprotein detection series of blood lipid detection.

In the blood, cholesterol is usually in the form of lipoprotein bound to apolipoprotein in a complex, which is divided into four types: high-density lipoprotein HDL, low-density lipoprotein LDL, very low-density lipoprotein VLDL and chylomicrons, of which LDL It is involved in transporting cholesterol to peripheral cells, and HDL is responsible for absorbing cholesterol from cells. At present, the detection of low-density lipoprotein is mainly to first monitor the total cholesterol content, high-density lipoprotein content and triglyceride content to calculate the LDL concentration. LDL-C=TC-HDL-C-TG/2.2(in mmol/L), (2) LDL-C=TC-HDL-C-TG/5(in mg/dl).

In the detection of total cholesterol, cholesterol ester is first hydrolyzed to cholesterol and fatty acid by cholesterol esterase CHE, and then it is oxidized to 4-cholesterenone by cholesterol oxidase to generate hydrogen peroxide, which is then coupled with DAOS and 4-AAP to generate chromogenic reaction with hydrogen peroxide under the catalysis of POD. The concentration of total cholesterol can be determined by measuring the absorbance.

In the detection of triglycerides, triglycerides are hydrolyzed to glycerol and fatty acids in the presence of LPL; glycerol and ATP generate glycerol-3-phosphate and ADP under the catalysis of GK; glycerol-3-phosphate and oxygen generate dihydroxyacetone phosphate and hydrogen peroxide under the catalysis of GPO, and then coupled with 4-APP with chromogenic substrate as in the above steps Hydrogen peroxide produces chromogenic reaction and TG concentration is measured.

In the detection of HDL, double reagent is used. The first reagent contains polyanion and surfactant, selectively combines with VLDL and LDL, and inhibits COD in the second reagent. CEH plays a role in VLDH-CH and LDH-CH, thus selectively acts on HDL-CH. through CEH-COD-POD, the concentration of HDL can be determined by measuring the absorbance. Finally, the LDL concentration can be obtained by calculation.

In a word, the chromogenic reagent DAOS is mainly used to generate chromogenic reaction with hydrogen peroxide generated after a series of enzyme catalytic reactions with the target to be tested. In addition, kits produced by some company use ESPAS and ADPS as chromogenic substrate. This series developed by Desheng has other chromogenic substrates, which can be used for different biochemical tests according to their characteristics.