[Study of the arsenate reducted by common reducing agents]

To study the role of glutathione (GSH), cysteine (Cys), vitamin C (VC) and ferrous ion (Fe2+) in the reduction of arsenate [As (V)] and the characteristic of reduction.

The reaction conditions [(37 degrees C, pH7.0 phosphate buffer) and the concentrations of As (V) (3 micromol/L), GSH (60 mmol/L), Cys (60 mmol/L), VC (0-30 mmol/L) and Fe2+ (0-40 mmol/L)] were simulated in vitro. Arsenite[As(III)] and [As(V)] were determined by the high performance liquid chromatography-hydride generation-atomic fluorescence spectrometry (HPLC-HG-AFS).

The reduction, of As(V) and As(III) formation, increased with the concentration, of GSH (0-60 mmol/L), and reached a maximum values at the concentration of 60 mmol/L GSH, then decreased with the concentration of (60-80 mmol/L) GSH. -SH in sulfhydryl compound, could play an important role in the reduction of As(V), and at the concentration of 60 mmol/L -SH (both GSH and Cys) could reduce 60%, of As(V) to As(III) for 30 min. VC or Fe2+ could not reduce As(V) alone, but when the concentration of VC or Fe2+ reached to 10 mmol/L or 20 mmol/L, they could have a significantly synergistic effect with 60 mmol/L -SH on the reduction of As(V) (P < 0.01).

SH could reduce As(V) alone without any reductase. VC and Fe2+ could have a synergistic effect with -SH on the reduction of As(V).