GCLM also known as γ-GCS is the first rate limiting enzyme of glutathione synthesis. GCLM plays a crucial role as the rate-limiting enzyme in glutathione synthesis, a vital antioxidant that protects cells from oxidative stress and maintains cellular redox balance. GCLM is a heterodimer composed of a heavy catalytic subunit and a light regulatory subunit, which together respond to various physiological stimuli such as inflammation and oxidative stress. The human GCLM gene encoding the 367 amino acid catalytic subunit is located on chromosome 6p12, while the gene for the regulatory subunit is found on chromosome 1p22-p21. The formation of a reversible disulfide bond between the two subunits enhances GCLM enzyme′s activity, highlighting the importance of post-translational modifications in regulating function.