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. Author manuscript; available in PMC: 2007 Nov 1.
Published in final edited form as: J Mol Cell Cardiol. 2006 Sep 26;41(5):762–773. doi: 10.1016/j.yjmcc.2006.08.006

Figure 2. Post-translational modifications of Trx1.

Figure 2

Trx1 has five modifiable cysteines (closed circles). Two of them, namely Cys-32 and Cys-35, in the catalytic site are involved in the enzymatic activity of Trx1. Under oxidative stresses, Trx1 forms disulfide bonds (S-S) between Cys-32 and Cys-35 and/or between Cys-62 and Cys-69, or a mixed disulfide bond with glutathione, called glutathionylation (S-SG). The activity of Trx1 or the accessibility of TrxR1 to Trx1 is inhibited by these oxidative modifications. On the other hand, Trx1 can be modified by NO and peroxynitrite. Trx1 is nitrosylated at Cys-69 (S-NO), which leads to the enhanced activity of Trx1. Trx1 has Tyr-49, which is nitrated by peroxynitrite. Nitration of Tyr-49 irreversibly suppresses the activity of Trx1.