Catalysis-electrochemical determination of zeptomole enzyme and its application for single-cell analysis.
A novel electrochemical method for determination of zeptomole amounts of enzyme was developed by a combination of on-capillary enzyme-catalyzed reaction and electrochemical detection. A limit of detection (LOD) of zeptomole (zmol, 10(-)(21) mol) was achieved by monitoring the product of the enzyme-catalyzed reaction. In this method, after enzyme molecules were electrokinetically injected into the capillary, they were electromigrated to the section of the capillary immersed in a warm water bath, where the enzyme molecules reacted with the enzyme substrates in the running buffer in the presence of the activator of the enzyme-catalyzed reaction. Then the electroactive product zone of the enzyme-catalyzed reaction was electromigrated to the horn-shaped outlet of the capillary and electrochemically detected by a carbon fiber disk bundle electrode at a constant potential. Glucose-6-phosphate dehydrogenase (G6PDH) was chosen as the model enzyme. A LOD of 1.3 zmol was achieved. This method was applied to determine zeptomoles of G6PDH in individual human erythrocytes.
Sun
Xuemei
X
School of Chemistry and Chemical Engineering, Shandong University, Jinan 250100, China.
Jin
Wenrui
W
D002384:Catalysis; D004563:Electrochemistry; D019075:Electrophoresis, Capillary / Q000379:methods; D004912:Erythrocytes / Q000166:cytology / Q000187:drug effects / Q000201:enzymology*; D005954:Glucosephosphate Dehydrogenase / Q000032:analysis* / Q000378:metabolism*; D006801:Humans; D008274:Magnesium / Q000494:pharmacology; D012680:Sensitivity and Specificity; D012996:Solutions
D012996:Solutions; D005954:Glucosephosphate Dehydrogenase; D008274:Magnesium