GSTK1 (glutathione S-transferase kappa 1) is a mitochondrial and peroxisomal enzyme that catalyzes glutathione conjugation reactions, with significant activity toward the model substrate 1-chloro-2,4-dinitrobenzene 1. Beyond its classical detoxification role, GSTK1 serves multiple cellular protective functions. The enzyme acts as a key regulator of adiponectin biosynthesis and multimerization, with its expression levels negatively correlated with obesity in both mice and humans 2. GSTK1 protects against metabolic dysfunction by regulating mitochondrial quality control, promoting mitochondrial biosynthesis and fusion while inhibiting excessive fission and mitophagy through interaction with the PGAM5/DRP1 complex 3. In disease contexts, GSTK1 demonstrates tumor suppressor activity in hepatocellular carcinoma via L-carnitine metabolism regulation 3 and provides cardioprotection during sepsis by maintaining mitochondrial function and suppressing cGAS/STING-dependent inflammation and pyroptosis 4. The enzyme also contributes to reticulophagy regulation through interaction with RETREG1/FAM134B, protecting against tubular injury in diabetic nephropathy 5. Genetic polymorphisms in the GSTK1 promoter significantly alter gene expression and are associated with insulin secretion and fat deposition 6, highlighting its clinical relevance in metabolic disorders.