This entry represents a widespread protein family known as MAPEG (Membrane Associated Proteins in Eicosanoid and Glutathione metabolism) []. This group of membrane associated proteins with highly divergent functions, such as the metabolism of eicosanoids [, ]. Included are:5-lipoxygenase activating protein (gene FLAP), which seems to be required for the activation of 5-lipoxygenase.Leukotriene C4 synthase (), which catalyses the production of LTC4 from LTA4. The structure of human LTC4S was solved by X-ray crystallography []. Microsomal glutathione S-transferase II () (GST-II), which also produces LTC4 from LTA4. These enzymes play an important role in the resistance to temperature stresses and lipid peroxidation [, ]. Prostaglandin E synthase, which catalyses the synthesis of PGE2 from PGH2 (produced by cyclooxygenase from arachidonic acid). Because of structural similarities in the active sites of FLAP, LTC4 synthase and PGE synthase, substrates for each enzyme can compete with one another and modulate synthetic activity.
