IBTC protected against MAP-inhibition of AChE and BChE in human erythrocyte ghosts (Fig. 5A and B). Treatment with MAP plus IBTC (at 10, 25, 50, and 100 μM) resulted in significantly increased cholinesterase activity compared to MAP alone (Fig. 5A and B). IBTC also significantly (p < 0.05) reactivated the AChE and BChE enzyme activities at concentrations of 10, 25, 50, and 100 μM

( Fig. 6A and B) compared to MAP alone. Since different enantiomers of methamidophos can bind to Ser203, Sp and Rp we performed docking studies with both Sp (SGX) and Rp (SGR) enantiomers of MAP-inhibited AChE from Mus musculus (PDB code: 2jge) ( Fig. 7). In the Rp conformation of methamidophos, IBTC was located in the active site between the peripheral anionic site (PAS) (Tyr124) and the internal anionic site (Tyr341). The binding energy was −9.2 kcal/mol for the Rp enantiomer. The thiocarbonyl group was 7.707 angstroms from the phosphate of SGR203, and the hydrazinic nitrogen http://www.selleckchem.com/products/Vorinostat-saha.html of the thiosemicarbazone function was 2.873 Å from the carboxylic oxygen of residue Asp74 and 3.305 Å from the oxygen of residue Tyr341. The terminal thioamidic nitrogen hydrogen bonded with residue Tyr124 of the peripheral anionic site. The other fragment of the molecule

was located close to the internal anionic site and stabilized by hydrogen bonds with residues Thr83 (nitrogen of the indole group) and Tyr337 (hydrogen bond with the amidic oxygen and the iminic nitrogen present on the thiosemicarbazone function). Only one cation–Pi interaction occurred between IBTC and the enzyme active Belnacasan clinical trial site, which was between the aromatic ring from the terminal thioamidic function and phosphate of the SER203. In the Sp conformation of methamidophos, similar to the Rp enantiomer of the serine modified by MAP, IBTC was stabilized in the active site between the peripheral anionic site (PAS) (Tyr124) and the internal anionic site (Tyr341). The binding energy was −8.95 kcal/mol.

The thiocarbonyl group was 6.311 Å from the phosphate of Amisulpride SGX203 and the hydrazinic nitrogen of the thiosemicarbazone function was 2.818 Å from the carboxylic oxygen of residue Asp74 and 3.271 Å from the oxygen of residue Tyr341. In this conformation (SGX), the sulfur group was closer to the phosphate of the modified serine than in the SGR conformation. The aromatic ring from the terminal thioamidic function was stabilized in a hydrophobic region between the PAS (Tyr337 and Tyr341) and the acyl binding pocket (Phe338). The amidic oxygen formed a hydrogen bond with residue Tyr337 as well as with the iminic nitrogen. There was also a hydrogen bond between residue Thr87 and the iminic nitrogen. Pi interactions did not directly occur with the molecule. One purpose of our study was to investigate the potential toxic properties of IBTC, a compound that has been investigated in many biological models of oxidative stress. In our previous study (Barcelos et al.