The Marine Mollusc Turbo radiatus Glutathione S-Transferase Isolation and Biochemical Characterization: Antibacterial Effect and Cytotoxicity Against Different Cancer Cell Lines

Glutathione S-transferases (GSTs) in aquatic organisms are extensively utilized as biomarkers for monitoring environmental contamination due to their ability to detoxify numerous pollutants. In this study, a GST enzyme from marine snails Turbo radiatus (TrGST) was purified through successive chromatographic separations on DEAE-cellulose, Sephacryl S-300, and glutathione-sepharose columns. TrGST was purified with 181.7-folds, 47.4% recovery and a specific activity of 194.4 Umg^-1. Molecular weight of TrGST, as determined by gel filtration, was 47 kDa. The SDS-PAGE analysis revealed TrGST as a single band of 23.4 kDa, indicating a homodimer protein of two identical subunits. The isoelectric point (pI) of TrGST was located at pH 6.1. The purified TrGST had Km values of 1.67 and 0.55 mM for CDNB and GSH with corresponding Vmax values of 0.72 and 0.4U/ mg, respectively. TrGST exhibited maximal activity at pH 8.4. The ions Co²⁺ and Mg²⁺ increased TrGST activity, while Mn²⁺, Cu²⁺, and Fe²⁺ suppressed it. TrGST was strongly inhibited by quercetin, lithocholic acid, cumene hydroperoxide, hematin, and triphenyltin chloride, with triphenyltin chloride being the most potent inhibitor showing noncompetitive inhibition with a Ki value of 0.125µM. TrGST revealed significant inhibition against certain bacterial strains; however, no inhibition was observed against others, indicating selective antimicrobial effects. TrGST exhibited strong cytotoxic effects against prostate cancer (PC3) and hepatocellular carcinoma (HepG2) cell lines, while showing weak activity against the colon cell line HCT116 and no effect on lung carcinoma cells (A549). The obtained results indicated that the TrGST protein may have the potential to serve as a tool for developing antibacterial and anti-cancer drugs in the future.