Amperometric determination of high-density lipoprotein cholesterol using polyethylene glycol-modified enzymes and a peroxidase-entrapped electrode.
A peroxidase-entrapped and ferrocene-embedded carbon paste (POD-Fc-CP) electrode allows a highly sensitive detection of H2O2 at levels as low as 10 nmol/L with practically no interference by coexisting substances, turbidity or coloration of samples. The electrode was applied to the amperometric determination of high-density lipoprotein (HDL)-cholesterol in a very small volume (1-2 microL) using polyethylene glycol (PEG)-modified cholesterol esterase and cholesterol oxidase without prior precipitation or separation of HDL. PEG-modified enzymes exhibit a selective activity toward HDL-cholesterol in the presence of dextran sulphate and MgCl2 to generate H2O2. The HDL-cholesterol concentrations of human serum samples determined by this method showed a good correlation with those determined by an ordinary spectrophotometric method using PEG-modified enzymes and peroxidase or by a conventional precipitation method.
Kinoshita
H
H
Kwassui Women's College, Nagasaki, Japan.
Torimura
M
M
Kano
K
K
Ikeda
T
T
D008076:Cholesterol, HDL / Q000097:blood*; D004563:Electrochemistry; D004800:Enzymes, Immobilized / Q000737:chemistry*; D006801:Humans; D010544:Peroxidases / Q000737:chemistry*; D011092:Polyethylene Glycols / Q000737:chemistry*; D012680:Sensitivity and Specificity; D013057:Spectrum Analysis
D008076:Cholesterol, HDL; D004800:Enzymes, Immobilized; D011092:Polyethylene Glycols; D010544:Peroxidases