Enzymatically-derived prostaglandin E2 (PGE2) is an optically pure compound whereas PGE2 derived from the free radical-catalyzed peroxidation of arachidonate is a racemic mixture. Ent-PGE2 is the opposite enantiomer of PGE2. Significant amounts of racemic PGE2 (rac-PGE2) are generated in vitro and in vivo in settings of oxidative stress via the isoprostane pathway. A proposed mechanism for the formation of rac-PGE2 involves the base catalyzed equilibration from 15-E2t-isoprostane (8-iso-PGE2), generated from the 15-H2t-isoprostane endoperoxide.
5-Fluorouridine 5'-O-β-D-galactopyranoside, also known as 5'-O-β-D-galactosyl-5-fluorouridine, is a prodrug of 5-Fluorouridine. 5-Fluorouridine 5'-O-β-D-galactopyranoside can be enzymatically converted by β-D-galactosidase into 5-Fluorouridine, which is a highly effective antineoplastic agent.
2′-O-(2-Methoxyethyl)guanosine (2'-O-MOE-rG), a modified nucleoside, can be enzymatically converted from 2′-O-(2-methoxyethyl)-2,6-diaminopurine riboside by adenosine deaminase. However, this compound is not readily phosphorylated by cytosolic nucleoside kinases, and it cannot be incorporated into cellular DNA or RNA.
11(S)-HETE, an (S) enantiomer of 11(R)-HETE and a type of oxylipin, is non-enzymatically synthesized from arachidonic acid. Compared to its counterpart, 11(S)-HETE levels are found to be elevated in both isolated human plasma and serum, as well as in LPS-stimulated isolated human plasma. Notably, patients with allergic rhinitis exhibit a decrease in 11(S)-HETE levels in their serum following one year of double-mite subcutaneous immunotherapy (DM-SCIT), correlating with an enhanced quality of life, particularly in aspects related to rhinoconjunctivitis.
Oxidized low-density lipoprotein (oxLDL) encompasses low molecular weight entities that facilitate monocyte differentiation and activate polymorphonuclear leukocytes. A substance, recently isolated and purified from oxLDL and identified as azelaoyl PC, exemplifies this. Similarly, Butanoyl PAF, a compound closely related to azelaoyl PC, maintains over 10% of the agonist potency of platelet-activating factor (PAF). Notably, Butanoyl PAF's concentration in oxLDL surpasses that of enzymatically generated PAF by more than 100-fold, making it a significant signalling molecule within oxLDL.
Prostaglandin D2 (PGD2) is one of the five principal prostaglandins enzymatically derived from PGH2. It is abundantly generated in the cerebrospinal fluid (CSF) by lipocalin-type PGD synthase and in peripheral regions by myeloid cells, such as mast cells and basophils, via leukocyte-type PGD synthase. The compound 1,25-trans-PGD2 is an isomer of PGD2, characterized by the alteration of the double bond between carbons 5 and 6 from cis(Z) to trans(E). This trans isomer, found as a 2-5% impurity in most commercial PGD2 bulk drug preparations, is primarily synthesized as an analytical standard to identify and quantify this impurity. Based on existing studies of trans isomers of F-type prostaglandins, 5-trans-PGD2 likely exhibits biological activity comparable to its cis isomer, although no specific published reports confirm this for 5-trans-PGD2.
1,3-Diarachidoyl glycerol, a diacylglycerol featuring arachidic acid at the sn-1 and sn-3 positions, is identified within enzymatically randomized pig lard.