Catalyzes a base-exchange reaction in which the polar head group of phosphatidylethanolamine (PE) or phosphatidylcholine (PC) is replaced by L-serine. PTDSS2 is specific for phosphatatidylethanolamine and does not act on phosphatidylcholine.
The chemical reactions and pathways resulting in the formation of phosphatidylserines, any of a class of glycerophospholipids in which the phosphatidyl group is esterified to the hydroxyl group of L-serine.
IEAUniPathway
Enzymatic activity
This protein acts as an enzyme. It is known to catalyze the following reaction
PS (phosphatidylserine) in mammalian cells is synthesized by two distinct base-exchange enzymes, PSS1 (PS synthase 1) and PSS2, which are responsible for the conversion of PC (phosphatidylcholine) and PE (phosphatidylethanolamine) respectively into PS in intact cells. The PS synthesis in cultured mammalian cells is inhibited by exogenous PS, and this feedback control occurs through inhibition of PSSs by PS. In the present study, we purified epitope-tagged forms of human PSS1 and PSS2. The purified PSS2 was shown to catalyse the conversion of PE, but not PC, into PS, this being consistent with the substrate specificity observed in intact cells. On the other hand, the purified PSS1 was shown to catalyse the conversion of both PC and PE into PS, although PSS1 in intact cells had been shown not to contribute to the conversion of PE into PS to a significant extent. Furthermore, we found that the purified PSS2, but not the purified PSS1, was inhibited on the addition of PS to the enzyme assay mixture, raising the possibility that there was some difference between the mechanisms of the inhibitory actions of PS towards PSS1 and PSS2.
Protein involved in the synthesis of lipids, a diverse class of compounds which are insoluble in water but soluble in organic solvents. They include fats, oils, triacylglycerols, fatty acids, glycolipids, phospholipids and steroids.
Protein involved in the biochemical reactions of lipids. Lipids are a diverse class of compounds which are insoluble in water but soluble in organic solvents. They include fats, oils, triacylglycerols, fatty acids, glycolipids, phospholipids and steroids.
Protein involved in the synthesis of phospholipids, the major lipid component of most cellular membranes. Phospholipids are usually composed of two fatty acid chains esterified to two of the carbons of glycerol phosphate, the phosphate being esterified to a hydroxyl group of another hydrophilic compound, such as choline, ethanolamine or serine.
Protein involved in the metabolism of phospholipids, the major lipid component of most cellular membranes. Phospholipids are usually composed of two fatty acid chains esterified to two of the carbons of glycerol phosphate, the phosphate being esterified to a hydroxyl group of another hydrophilic compound, such as choline, ethanolamine or serine.
A reference proteome is a set of protein sequences derived from a complete proteome which constitutes a defined standard for a particular user community. Reference proteomes are manually defined according to a number of criteria. They cover the proteomes of well- studied model organisms and other proteomes of interest for biomedical and biotechnological research. Reference proteomes have been selected to provide broad coverage of the tree of life, and constitute a representative cross-section of the taxonomic diversity to be found within UniProtKB.