C. Fernandezsanchez et A. Costagarcia, 3-INDOXYL PHOSPHATE - AN ALKALINE-PHOSPHATASE SUBSTRATE FOR ENZYME IMMUNOASSAYS WITH VOLTAMMETRIC DETECTION, Electroanalysis, 10(4), 1998, pp. 249-255
The voltammetric detection of the indigo blue generated when 3-indoxyl
phosphate is used as the substrate for the alkaline phosphatase enzym
e has been studied. This molecule undergoes a reversible process on a
carbon paste electrode at 0.0 V in 0.1 M HClO4 and at around -0.4 V in
0.1 M Tris buffer. Moreover, it is strongly adsorbed on the electrode
surface. For these reasons, a comparative study of the electrochemica
l behavior of both, substrate and product, was carried out by cyclic v
oltammetry and alternating current voltammetry. At the same time, the
adsorption of an alkaline phosphatase labeled immunoglobulin G on a ca
rbon paste electrode has been explored by these two techniques, using
3-indoxyl phosphate as the enzymatic substrate.