TLK117, the active metabolite of TLK199, selective inhibits Glutathione S-transferase P1–1 (GSTP1-1) with a K i of 0.4 μM for GSTP. TLK117 also competitively inhibits glyoxalase I with a K i of 0.56 μM.
In Vitro
TLK117 is the most specific GSTP inhibitor to date, with a binding affinity greater than GSH itself and a selectivity for GSTP over 50-fold greater than the GSTM and GSTA classes (K i =0.4 μM). TER 117 is developed as a GST P1-1 isoenzyme inhibitor to circumvent the indicated contribution of GST P1-1 to drug resistance of tumor cells. To facilitate the cellular uptake of TER 117, it is delivered as a diethyl ester (TER 117 DEE, also called TER 199). TER 117 is found to be a competitive inhibitor of both GST P1-1 and glyoxalase I. MCE has not independently confirmed the accuracy of these methods. They are for reference only.
In Vivo
Oropharyngeal administration of the GSTP inhibitor, TLK117, at a time when fibrosis is already apparent, attenuated bleomycin- and AdTGFβ-induced remodeling, α-SMA, caspase activation, FAS S-glutathionylation, and total protein S-glutathionylation. Four hours after administration of 50 mg/kg TLK117, GSTP activity is strongly decreased and remains decreased by about 60% for at least 24 hours. MCE has not independently confirmed the accuracy of these methods. They are for reference only.
