Electrochemical piezoelectric quartz crystal impedance study on the interaction between concanavalin A and glycogen at Au electrodes.

The carbohydrate research has emerged as a "new frontier" in chemical/biological field. The binding of lectin with carbohydrate is one of the important courses of life activities. The report studies concanavalin A (Con A)-glycogen interaction on gold electrode surfaces by electrochemical piezoelectric quartz crystal impedance (EPQCI) method. The piezoelectric quartz crystal (PQC) parameters, resonant frequency shift (Deltaf(0)) and the motional resistance change (DeltaR(1)), and the electrochemical impedance (EI) parameters, electrolyte resistance change (DeltaR(s)) and the double layer capacitance change (DeltaC(s)), were measured and discussed simultaneously. Two methods were adopted for measuring the Con A-glycogen association. Based on EPQCI measurement during Con A reaction with glycogen adsorbed on Au electrode, association constant K(a) and the amount of the binding sites s calculated are 1.48 x 10(6) M(-1) and 4.09, respectively. Based on single PQC measurement of glycogen reaction with Con A assembled on Au electrode, K(a) was estimated to be 1.26 x 10(6) M(-1).