Troponin I fast skeletal muscle, Troponin I fast-twitch isoform, TNNI2, DA2B, FSSV, fsTnI, AMCD2B. Thioredoxin-1, Trx-1, trxA, fipA, tsnC, b3781, JW5856.Thioredoxin Recombinant Thioredoxin was purified from E. coli harboring its gene. Each mg of protein contains 20mM phosphate buffer pH 7.4. TRX activity is assayed by measuring the change in absorbance at 650 nm at 25°C using 0.13µM bovine insulin containing 0.33mM DTT (pH 6.5). The specific activity was found to be 3IU/mg.