FIGURE 3.
MALDI-TOF spectra of trypsin-digested hAS3MT. The hAS3MT was separated by 12% non-reducing SDS-PAGE and alkylated by 20 mm iodoacetamide after having catalyzed the arsenite methylation at 37 °C for 60 min. The reaction system contained hAS3MT (4.0 μm), AdoMet (1.0 mm), iAs3+ (1.0 μm), phosphate buffer (25 mm, pH 7.0), and different reductant. The reductants were TCEP (B), cysteine (C), and GSH (D) at 0.7, 10, and 7 mm, respectively. The protein under natural condition was used as a control (A). Results are the average of three determinations.