In vitro, possesses glutathione S-transferase activity toward 1-chloro-2,4-dinitrobenzene (CDNB) and benzyl isothiocyanate (BITC), and glutathione peroxidase activity toward cumene hydroperoxide and linoleic acid-13-hydroperoxide. May be involved in the conjugation of reduced glutathione to a wide number of exogenous and endogenous hydrophobic electrophiles and have a detoxification role against certain herbicides. glutathione + RX = a halide anion + an S-substituted glutathione + H(+) Redox-regulated enzyme; in oxidative stress conditions methionine oxidation ensure a thermodynamic and structural compensatory mechanism to guarantee H(2)O(2) peroxidase activity despite transferase activity inhibition. kcat is 0.5 sec(-1) with glutathione as substrate (in oxidative conditions) (PubMed:29732642). kcat is 0.85 sec(-1) with glutathione as substrate (in reductive conditions) (PubMed:29732642). kcat is 0.72 sec(-1) with 1-chloro-2,4-dinitrobenzene as substrate (in oxidative conditions) (PubMed:29732642). kcat is 0.98 sec(-1) with 1-chloro-2,4-dinitrobenzene as substrate (in reductive conditions) (PubMed:29732642). By zinc in roots and benoxacor. Oxidated at Met-35, Met-118, Met-123 and Met-184 in oxidative stress conditions (e.g. hydrogen peroxide H(2)O(2)). Belongs to the GST superfamily. Phi family.