Phospholipids sphingomyelins

Structural components and function of sphingomyelin The alcohol sphingosine attached to a long-chain fatty acid produces a ceramide. Addition of a phosphorylcholine produces the phospholipid sphingomyelin, which is the only significant sphingophospholipid in humans. It is an important constituent of myelin. 

Adinehzadeh M, Reo NV. 1998. Effects of peroxisome proliferators on rat liver phospholipids Sphingomyelin degradation may be involved in hepatotoxic mechanism of perfluorodecanoic acid. Chem Res Toxicol 11 428-440. 

Sphingolipids are derivatives of ceramide (N-acylsphingosine, compare Chapter 1.4). Most eukaryotic glycolipids and the phospholipid sphingomyelin contain ceramide as the hydrophobic backbone. 

The complex lipids in milk fat are comprised of the phosphoglycerides, phosphatidyl choline, phosphatidyl serine, phosphatidyl ethanolamine, phosphatidylinositol and plasmalogens. Also, the non-glyceride phospholipid, sphingomyelin, occurs in important amounts (Jensen, 2002). Bitman and Wood (1990) described the distribution of phospholipid classes in bovine milk and their fatty acid composition. The phospholipids comprise about 1% and cholesterol 0.4—0.5% of the total milk fat. These occur almost completely in the milk fat globule membrane. 

Sphingolipids comprise glycolipids (gangliosides and cerebrosides) and the phospholipid, sphingomyelin. These compounds, too, are important membrane constituents. The biosynthesis of sphingolipids involves the common intermediate ceramide (Fig. 13-15). 

In blood, phosphatidylcholine is quantitatively the most important phospholipid. Sphingomyelin is present in varying amounts in perhaps all of the animal organs, most of it in the soft organs, and to a lesser degree in skeletal muscles and eggs (4). Total blood contains about 0.2% to 0.3% phospholipids. In plasma and serum, phosphatidylcholine predominates, whereas in corpuscles, phosphatidylethanolamine and sphingomyelin constitute the bulk of phospholipids. Most workers have found... 

Chatterjee, S., Kolmakova, A., Miller, M. 2006. The role of the phospholipid sphingomyelin in heart disease. Curr. Opin. Investig. Drugs 7 219-228. 

Lipids occur widely in nature. For examples, phospholipids are the main building blocks of biological membranes. Lipids exist in a variety of distinct forms, such as fatty acids, acylglycerols, phospholipids, sphingomyelins, glycosphingolipids, gangliosides, steroids, bile acids, prostaglandins, and leukotrienes. Some of lipids are structurally simple molecules, but others are complex molecules. Many are amphiphilic compounds. 

K., and Hanaoka, K. (1996). Sensitive method for the determination of pulmonary surfactant phospholipid/sphingomyelin ratio in human amniotic fluids for the diagnosis of respiratory distress syndrome by thin-layer chromatography-immunostain-ing. Anal. Biochem. 238 29-33. 

Edgar, G. W. F. Alkali-stable choline phospholipids ( sphingomyelin ) in tissue of amaurotic idiocies. In Cerebral Sphingolipidoses. Ed. S. M. Aronson, and B. W. Volk, p. 165. New York Academic Press 1962. 

Cholesterol, free Cholesterol, esterified Total phospholipids Sphingomyelin ... 

Total lipids Cholesterol Phospholipids Sphingomyelin Cephalins Lecithin Cerebroside Sulfatide... 

In addition to being involved in the production of phosphatidylcholine, CDP-choline is also used for the formation of the sphingosine-containing phospholipid, sphingomyelin (Figure 7.1). The major pathway for the formation of sphingomyelin transfers phosphorylcholine from CDP-choline to a ceramide (section 7.4.5 and Figure 7.14). 

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