Method for quantifying the amount of cholesterol in high-density lipoprotein 3

Abstract

A method that enables quantification of cholesterol in high-density lipoprotein 3 (HDL3) in a test sample without requiring a laborious operation is disclosed. The method for quantifying cholesterol in HDL3 comprises: Step 1 wherein phospholipase and/or sphingomyelinase is/are allowed to act on a test sample to transfer cholesterol to the outside of the reaction system; and Step 2 wherein cholesterol remaining in the reaction system is quantified. The method enables specific quantification of HDL3 cholesterol in a test sample using an automatic analyzer without requirement of a laborious operation such as ultracentrifugation or pretreatment. Further, quantification of the HDL2 cholesterol level can also be carried out by subtracting the HDL3 cholesterol level from the total HDL cholesterol level obtained by a conventional method for quantifying the total HDL cholesterol in a test sample.

1 . A method for quantifying cholesterol in high-density lipoprotein 3, said method comprising:
 Step 1 wherein phospholipase and/or sphingomyelinase is/are allowed to act on a test sample to transfer cholesterol to the outside of the reaction system; and   Step 2 wherein cholesterol remaining in the reaction system is quantified.   
     
     
         2 . The method according to  claim 1 , wherein said phospholipase is phospholipase C and/or phospholipase D. 
     
     
         3 . The method according to  claim 1  or  2 , wherein said Step 1 is carried out in the presence of a surfactant(s) that react(s) with lipoprotein other than high-density lipoprotein 3. 
     
     
         4 . The method according to  claim 3 , wherein said surfactant is at least one nonionic surfactant which is polyoxyethylene distyrene-modified phenyl ether. 
     
     
         5 . The method according to  claim 3 , wherein said surfactant is at least one anionic surfactant selected from the group consisting of polyoxyethylene-polyoxypropylene condensates, amide ether sulfate and polyoxyethylene-stearylamine. 
     
     
         6 . The method according to  claim 3 , wherein said surfactant is at least one amphoteric surfactant selected from the group consisting of coconut oil fatty acid-amidopropyldimethyl-aminoacetic acid betaine, alkyl dimethyl-aminoacetic acid betaine and lauryl betaine. 
     
     
         7 . The method according to  claim 3 , wherein said surfactant is a cationic surfactant which is lauryl trimethyl ammonium chloride. 
     
     
         8 . The method according to  claim 1 , wherein said Step 2 is carried out in the presence of a surfactant(s) that react(s) at least with high-density lipoprotein 3. 
     
     
         9 . The method according to  claim 8 , wherein said surfactant used in Step 2 is at least one nonionic surfactant selected from the group consisting of polyoxyethylene distyrene-modified phenyl ether, polyoxyethylene lauryl ether and p-isooctyl polyoxyethylene phenol formaldehyde polymers. 
     
     
         10 . The method according to  claim 8 , wherein said surfactant used in Step 2 is at least one amphoteric surfactant selected from the group consisting of lauryl dimethyl-aminoacetic acid betaine and polyoxyethylene lauryl ether. 
     
     
         11 . The method according to  claim 8 , wherein said surfactant used in Step 2 is at least one cationic surfactant which is fatty acid series phosphoric acid ester. 
     
     
         12 . The method according to  claim 8 , wherein said surfactant used in Step 2 is at least one nonionic surfactant having an HLB of 11 to 14, selected from the group consisting of polyoxyethylene distyrene-modified phenyl ether, polyoxyethylene tribenzyl phenyl ether, polyoxyalkylene alkyl ether, polyoxyethylene polycyclic phenyl ether and polyoxyethylene cumyl phenyl ether. 
     
     
         13 . The method according to  claim 8 , wherein said surfactant used in Step 2 is at least one imidazoline-type amphoteric surfactant. 
     
     
         14 . The method according to  claim 8 , wherein said surfactant used in Step 2 is at least one nonionic surfactant selected from the group consisting of polyoxyethylene lauryl ether, polyoxyethylene alkyl ether and polyoxyethylene alkyl phenyl ether. 
     
     
         15 . The method according to  claim 8 , wherein said surfactant used in Step 2 is at least one anionic surfactant selected from the group consisting of lauryl alcohol alkoxylate and sodium polyoxyethylene-alkyl phenyl ether sulfate.