Fatty acid composition of phospholipids of myelin and synaptosomal proteolipid complexes from vertebrate brain

Age- and brain region-specific effects of dietary vitamin K on myelin sulfatides

“…Myelin fractions were isolated from the brain regions by differential centrifugation using a modified procedure as described previously [36]‥ Briefly, individual brain regions (cortex, striatum and hippocampus) were homogenized in 0.32 M sucrose buffer containing protease inhibitors to prevent protease activation and protein cleavage. Crude membrane fractions (P-2) were separated from the crude nuclear fractions in each of the brain regions by low speed centrifugation, followed by ultra centrifugation on a Ficoll gradient (7% and 14%) for separation of myelin fractions.…”

“…Briefly, sulfatides were purified from the myelin lipids prior their quantitative assessment. Specifically, glycolipids, including gangliosides and other water-soluble myelin constituents, were removed by the chloroform-methanol (2:1 vol/vol) Folch procedure as described previously [36]. The potentially remaining traces of glycolipids and other water-soluble myelin constituents were further removed by washing the lower phase with “pure solvents upper phase” prepared with 0.1M KCl.…”

“…Sulfatides were then purified from the other classes of myelin lipids (i.e., phospholipids, cholesterol, etc.) by two dimensional high performance thin layer chromatography [36]. Sulfatides were identified using sulfatide standards (Sigma Chemical Co., St. Louis; cat.# S1006).…”

Vitamin K and Sphingolipid Metabolism: Evidence to Date

“…Of the brain membranes, myelin and neuronal plasma membranes are particularly enriched with sphingolipids. 26,27 Polysialogangliosides, which belong to the gangliosides (a subclass of glycosphingolipids), have several sialic acids in their structure. Polysialogangliosides are the predominant constituents of neuronal plasma membranes, whereas myelin membranes are primarily represented by cerebrosides, sulfatides, and monosialogangliosides (i.e., gangliosides with one sialic acid in their structure).…”

“…In contrast to myelin, these neuronal plasma membranes are composed of about 40% lipids and 60% protein and also have a higher fluidity. 27,40 As such, neuronal sphingolipids are primarily charged molecules (i.e., gangliosides, sulfatides, and sphingomyelin), and are almost exclusively located on the outer layer of neuronal membranes. 22…”