Leukotriene C4 synthase

Content sourced from Wikipedia, licensed under CC BY-SA 3.0.

Leukotriene C4 synthase (LTC4S) is an enzyme in humans encoded by the LTC4S gene. It belongs to the MAPEG family of membrane proteins and forms a trimer that sits in the outer nuclear membrane and the endoplasmic reticulum, where it works with 5-lipoxygenase-activating protein (FLAP) as part of leukotriene production.

LTC4S catalyzes the first step in making cysteinyl leukotrienes by converting leukotriene A4 and the antioxidant glutathione into leukotriene C4. Leukotrienes are powerful inflammatory mediators linked to allergic reactions and asthma.

The LTC4S gene is located on chromosome 5q35.3 in humans, and the enzyme has orthologs in other species, such as mice, reflecting its conserved role in inflammation. The protein is a transmembrane enzyme related to the glutathione-transferase family, but its main job here is leukotriene synthesis.