Reaction: Ac-PTGS2 dimer oxidises DPAn-3 to 17-HDPAn-3
- in pathway: Biosynthesis of electrophilic ω-3 PUFA oxo-derivatives
Normally, cyclooxygenases (COX) carry out stereospecific oxygenation of arachidonic acid to generate prostaglandins.Inflammation results in activated macrophages in which, when treated with aspirin (acetylsalicylic acid, ASA), dimeric cyclooxygenase 2 (COX2, PTGS2 dimer) can be acetylated. ASA covalently modifies PTGS2 by acetylating a serine residue at position 530 within the cyclooxygenase active site (Lucido et al. 2016). Ac-PTGS2 dimer changes the oxygenation stereospecificity towards its substrates, perhaps by steric shielding effects (Tosco 2013), producing a shift in lipid mediator production. Ac-PTGS2 dimer is able to incorporate molecular oxygen into ω-3 fatty acid docosapentaenoic acid (DPAn-3) to form 17-hydroxy-docosapentaenoic acid (17-HDPAn-3) (Serhan et al. 2002, Groeger et al. 2010).
Reaction - small molecule participants:
17-HDPAn-3 [cytosol]
DPAn-3 [cytosol]
O2 [cytosol]
Reactome.org reaction link: R-HSA-9027607
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Reaction input - small molecules:
(7Z,10Z,13Z,16Z,19Z)-docosapentaenoate
dioxygen
Reaction output - small molecules:
(7Z,10Z,13Z,15E,19Z)-17-hydroperoxydocosapentaenoic acid
Reactome.org link: R-HSA-9027607