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Background: The glutathione S-transferases (GSTs) are family of enzymes that are notable for their role in phase II detoxification reactions. Antibiotics have been reported to have several adverse effects on the activity of the enzymes in mammals. Aim: The aim of this study was the structural and biochemical characterization of rat erythrocyte GST and understanding the effects of gentamicin, clindamycin, cefazolin, ampicillin and scopolamine butylbromide on the activity of human erythrocyte GST using rat as a model. Methods: The enzyme was purified by GSH-agarose affinity chromatography. In vitro GST enzyme activity was measured at 25°C using CDNB as a model substrate. IC50 of drugs was measured by activity % vs compound concentration graphs. Lineweaver Burk graphs were drawn to determine the inhibition type and Ki constants for the drugs. The structure of the enzyme was predicted via Protein Homology/analogy Recognition Engine. Results: In this study, GST was purified from rat erythrocyte with a specific activity of 6.3 EU/mg protein, 44 % yield and 115 fold. Gentamicin and clindamycin inhibited the enzymatic activity with IC50 of 1.69 and 6.9 mM and Ki of 1.70 and 2.36 mM, respectively. Ampicillin and scopolamine butylbromide were activators of the enzyme, while the activity of the enzyme was insensitive to cefazolin. The enzyme was further characterized by homology modeling and sequence alignment revealing similarities with human GST. Conclusion: Collectively, it could be concluded that gentamicin and clindamycin are the inhibitors of erythrocyte GST.

Surface functionalized nanostructures have outstanding potential in biological applications owing to their target-specific design. In this study, we utilized laboratory synthesized carbohydrate-derivatives (i.e., galactose, mannose, lactose, and cellobiose derivatives) for aqueous one-pot synthesis of gold (Au) and silver (Ag) nanostructure glycoconjugates (NSs), and iron metal-organic framework glycoconjugates (FeMOFs). This work aims to test whether differences in the surface chemistry of the inorganic nanostructures play roles in revealing their toxicities towards bacterial cells and cancerous cell lines. As of the first step, biological activity of AuNSs, AgNSs, and FeMOFs were tested against a variety of gram (−) and gram (+) bacterial strains, where AgNSs possessed moderate to high antibacterial activities against all the tested bacterial strains, while AuNSs and FeMOFs showed their bacterial toxicity mostly depending on the strain. Minimum inhibitory concentration (MIC) and Minimum bactericidal concentration (MBC) determination studies were performed for the nanostructure glycoconjugates, for which μg/mL MBC values were obtained such as (Cellobiose p-aminobenzoic acid_AgNS) CBpAB_AgNS gave 50 μg/mL MBC value for P.aeruginosaand S.kentucy. The activity of selected sugar ligands and corresponding glycoconjugates were further tested on MDA-MB-231 breast cancer and A549 lung cancer cell lines, where selective anticancer activity was observed depending on the surface chemistry as well. Besides, d-penicillamine was introduced to galectin specific sugar ligand coated AuNS glycoconjugates, which showed very strong anticancer activities even at low doses. Overall, the importance of this work is that the surface chemistry of the inorganic nanostructures can be critical to reveal their toxicity towards bacterial cells and cancerous cell lines.