PGE synthase (前列腺素E合成酶)

PGE synthase (Prostaglandin E synthase), which converts cyclooxygenase (COX)-derived prostaglandin H₂ (PGH₂) to PGE₂, is known to comprise a group of at least three structurally and biologically distinct enzymes. There are membrane-associated PGES (mPGES)-1, mPGES-2, and cytosolic PGES (cPGES).

mPGES-1 is a perinuclear protein that is markedly induced by proinflammatory stimuli and downregulated by anti-inflammatory glucocorticoids as in the case of COX-2. It is functionally coupled with COX-2 in marked preference to COX-1. mPGES-2 is synthesized as a Golgi membrane-associated protein, and the proteolytic removal of the N-terminal hydrophobic domain leads to the formation of a mature cytosolic enzyme. This enzyme is rather constitutively expressed in various cells and tissues and is functionally coupled with both COX-1 and COX-2. cPGES is constitutively expressed in a wide variety of cells and is functionally linked to COX-1 to promote immediate PGE₂ production.