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. 2014 Oct 17;27(11):1979–1989. doi: 10.1021/tx500313k

Figure 6.

Figure 6

Role of cysteine residues in methylation of MAs(III). Methylation of MAs(III) by cysteine mutants was assayed at the indicated times at 37 °C with 10 μM MAs(III), 1 μM hAS3MT, 1 mM SAM, 5 mM GSH, 10 μM Trx, 3 μM TR, and 0.3 mM NADPH. The reaction was terminated by addition of 10% (v/v) H2O2, final concentration. Protein was removed before analysis, and soluble arsenicals were analyzed by reversed-phase HPLC-ICP-MS. (A) Synthetic wild-type hAS3MT. (B) C32S mutant. (C) C61S mutant. (D) C32S/C61S double mutant. The C156S and C206S derivatives did not methylate MAs(III) (not shown).