Polarographic method for rapid microdetermination of cholesterol with cholesterol esterase and cholesterol oxidase.
Cholesterol concentrations in serum are enzymatically determined rapidly by use of a polarographic oxygen analyzer with a circuit modified to record simultaneously the amount and rate of oxygen consumption. The final assay system, assessed from the oxygen consumption value that we found to be optimum, consists of 1 ml of sodium phosphate buffer (0.6 mol/liter, pH 7.0) containing NaN3 (10 mg/liter), Triton X-100 surfactant (10 ml/liter), 0.4 U of cholesterol ester hydrolase, and 0.6 U of cholesterol oxidase. Oxygen consumption and cholesterol concentration are linearly related to 8.0 g/liter, and only 10 mul of serum is required. Replicate analyses of pooled serum by the present method demonstrated the following inter-run precision: mean = 1731 mg/liter, SD = 22.3 mg/liter, CV = 1.3%. Bilirubin and ascorbic acid were without effect on the present method, unlike the enzymatic colorimetric methods.
D002265:Carboxylic Ester Hydrolases / Q000378:metabolism; D002784:Cholesterol / Q000097:blood*; D006801:Humans; D006863:Hydrogen-Ion Concentration; D007700:Kinetics; D008722:Methods; D008832:Microchemistry; D009994:Osmolar Concentration; D010101:Oxygen Consumption / Q000187:drug effects; D010710:Phosphates / Q000494:pharmacology; D002787:Sterol Esterase / Q000378:metabolism
D010710:Phosphates; D002784:Cholesterol; D002265:Carboxylic Ester Hydrolases; D002787:Sterol Esterase