抄録
Low density lipoprotein cholesterol (LDL-C), high density lipoprotein cholesterol (HDL-C) and choline containing phospholipids in serum are enzymatically determined by use of a polarographic oxygen analyzer with a long life and high sensitive sensor to determine the low concentration of serum lipids.
The final assay system for cholesterol in the serum, assessed from the oxygen consumption value that we found to be optimum, consists of 1 ml of phosphate buffer (0.1mol/l, pH 7.3), containing 50 μmol of phenol, 0.5% sodium taurocholate as a surfactant, 5U of cholesterol ester hydrolase, 9U of cholesterol oxidase and for phospholipids in serum, consists of 1ml of Trishydrochloride buffer (0.05 mol/l, pH7.6) containing 25μmol of phenol, 0.1 % of Triton X 100 as a surfactant, 5.4 U of phospholipase D and 12 U of cholineoxidase.
Oxygen consumption and the concentration of cholesterol or choline containing phospholipids are lineary related to 2.5 g/l from 0.2 g/l using 50μl of serum within 60 seconds-incubation. Replicated analysis of cholesterol and phospholipids by the present method demonstrated the following inter-run precision; HDL-C, mean (mg/dl)±S. D., 39.0±0.60, c. v., 1.54 %, LDL-C, 116.0±0.70, c. v., 0.60 %, phospholipids, 194.0±6.0, c. v., 3.09.
Bilirubin and ascorbic acid were without effect on the present method unlike the enzymic colorimetric methods.
The correlationship of cholesterol and phospholipids between polarographic method and enzymic colorimetric method was well in normal serum.
