Studies on the interaction of paclitaxel with tubulin by an electrochemical method

Highly sensitive linear scanning voltammetry was developed for trace determination of the antitumor agent paclitaxel and the mechanism of the binding of paclitaxel to tubulin was studied. The results showed that the reaction of tubulin dimer with paclitaxel formed an electrochemically nonactive 2:2 complex units. Its stability constant was 2.85×1022. It suggested that the tubulin dimer had two binding sites for paclitaxel. The experiment showed that the binding sites of paclitaxel to tubulin dimer were different from that of Ca2+ to tubulin dimer, and the sulfhydryl residues and disulfide bonds of tubulin may not participate in the binding of paclitaxel with tubulin. The experiment also showed the paclitaxel could interact with bovine serum albumin.