sphingomyelins

Sphingomyelins (SMs) are bioactive sphingolipids found in mammalian cell membranes.1SMs make up 2-15% of the total organ phospholipid population but are found at higher concentrations in the brain and myelin sheaths surrounding peripheral nerves. They interact with cholesterol to control its distribution within cellular membranes and maintain cholesterol homeostasis in cells. SMs undergo hydrolysis by sphingomyelinase to form ceramides, which are sphingolipid mediators of intracellular signaling.2This product is a mixture of SMs, with variable fatty acyl chain lengths, isolated from buttermilk. [Matreya, LLC. Catalog No. 1329] 1.Slotte, J.P., and Ramstedt, B.The functional role of sphingomyelin in cell membranesEur. J. Lipid Sci. Technol.109(10)977-981(2007) 2.Shayman, J.A.SphingolipidsKidney Int.58(1)11-26(2000)

Sphingomyelins are complex membrane lipids composed of phosphorylcholine, sphingosine, and an acylated group, such as a fatty acid. Lysosphingomyelin is a naturally-occurring lipid which is produced by the removal of the acylated group of sphingomyelin by a deacylase. Lysosphingomyelin may, in turn, serve as a substrate for autotaxin, which removes choline to produce sphingosine-1-phosphate. The receptors and signaling pathways that are activated by lyso-sphingosine are diverse and vary between cell types. Lysosphingomyelin occurs naturally in plasma, is a constituent of lipoproteins, and is increased in some diseases, including dermatitis and Niemann-Pick disease.

Sphingosine (d16:1), an unconventional sphingolipid, is synthesized through enzymatic reactions starting with the condensation of myristoyl-CoA and serine by serine palmitoyltransferase long-chain base subunit 3 (SPTLC3), which shows a preference for myristoyl-CoA. This compound is found in minute quantities in its free form in human plasma and as a component of various plasma sphingolipids, such as sphingosine-1-phosphate, ceramides, sphingomyelins, and in brain cerebrosides, albeit at lower concentrations than the more common d18:1 sphingoid base. Sphingosine (d16:1) acts as an inhibitor of PKC in mixed micelle assays and diminishes superoxide production triggered by phorbol 12-myristate 13-acetate in isolated human neutrophils, as well as inhibiting the growth of CHO cells with IC50 values of 1 and 3.2 µM, respectively. Additionally, the concentration of sphingolipids containing sphingosine (d16:1) in the plasma is linked to the dietary consumption of saturated fatty acids and protein among ethnic Chinese populations.