Catalyzes the conjugation of leukotriene A4 with reduced glutathione (GSH) to form leukotriene C4 with high specificity (  ). Can also catalyze the transfer of a glutathionyl group from glutathione (GSH) to 13(S),14(S)-epoxy-docosahexaenoic acid to form maresin conjugate in tissue regeneration 1 (MCTR1), a bioactive lipid mediator that possess potent anti-inflammatory and proresolving actions .
Subcellular locations: Nucleus outer membrane, Endoplasmic reticulum membrane, Nucleus membrane
Detected in lung, platelets and the myelogenous leukemia cell line KG-1 (at protein level). LTC4S activity is present in eosinophils, basophils, mast cells, certain phagocytic mononuclear cells, endothelial cells, vascular smooth muscle cells and platelets.