ATG and ebselen synergically affected the Trx system activity in vitro. Trx system activity was determined using an insulin assay in the presence or absence of ATG and/or ebselen. A, wild-type Trx1. B, C62S/C73S Trx1. C, C69S Trx1. To perform the enzyme assay, 20 nm TrxR1, 0.2 mm NADPH, the indicated amounts of ATG, the indicated amounts of ebselen, and 3 μm Trx1 were added into the reaction solution, and then reactions were initiated by the addition of 0.16 mm insulin. D, 4.5 μm pre-reduced TrxR1 was incubated with 10 μm ATG and/or 50 μm ebselen for 20 min. Then, 48 μm Trx1 was incubated with the mixture for 30 min. The reaction mixtures were then subjected to SDS-PAGE gel in the absence (lanes 1-4) or presence (lanes 5-8) of DTT. M, protein marker. E, the reaction mixtures were subjected to Western blot analysis using Trx1 antibody (lanes 1 and 2) and TrxR1 antibody (lanes 3 and 4).