Determination of polyanion utilizing a promoted glucose oxidase enzymatic reaction by ε-poly-L-lysine

In this paper, a sensitive determination method for polyanion using a glucose oxidase (GOx) enzymatic reaction with ferricyanide ion is described. We previously reported that the GOx enzymatic reaction was significantly promoted by a cationic polymer of ε-poly-L-lysine (εPL), and the enzymatic reaction could be utilized for the determination of εPL. Generally, polycation stoichiometrically forms polyion complex with polyanion. Thus, it is expected that the promotion effect of εPL on the enzymatic reaction is interfered by polyanion, and the enzymatic reaction is also applicable to the determination of polyanion. Predictably, the promotion effect of εPL was stoichiometrically interfered by polyanions, such as polyvinyl sulfate and polyacrylate, and the interference effect allowed for the determination of the polyanions. The detection limit of polyanion was estimated to be ~ 0.3 μeq L^-1. As a preliminary application, the proposed method was applied to the determination of anionic polymer of heparin in a human plasma.