1.C.3.5.1
Prostaglandin-H2 D-isomerase,  PTGDS (PDS) of 190 aas and 1 N-terminal TMS.  It regulates the calcium channel forming VIC family member with TC# 1.A.1.11.9 (Gomez et al. 2023).  It catalyzes the conversion of PGH2 to PGD2, a prostaglandin involved in smooth muscle contraction/relaxation and a potent inhibitor of platelet aggregation (Zhou et al. 2010).  It is also involved in a variety of CNS functions, such as sedation, NREM sleep and PGE2-induced allodynia, and may have an anti-apoptotic role in oligodendrocytes. Binds small non-substrate lipophilic molecules, including biliverdin, bilirubin, retinal, retinoic acid and thyroid hormone, and may act as a scavenger for harmful hydrophobic molecules and as a secretory retinoid and thyroid hormone transporter.