Stratum sphingolipids

As the final outer stratum comeum is formed the phospholipid bilayer deteriorates and intercellular lipid layers are formed.k l These contain principally ceramides, cholesterol, and free fatty acids. Some sphingolipids are covalently attached to proteins.3... 

Wertz, P.W., et al. 1984. Sphingolipids of the stratum corneum and lamellar granules of fetal rat epidermis. J Invest Dermatol 83 193. 

Thewalt, J. et al., Models of stratum corneum intercellular membranes the sphingolipid headgroup is a determinant of phase behaviour in mixed lipid dispersions, Biochem. Biophys. Res. Commun., 188, 1247, 1992. 

Denda, M., Hori, J., Koyama, J., Yoshida, S., Namba, R., Takahashi, M., Horii, I., and Yamamoto, A., Stratum corneum sphingolipids and free amino acids inexperimentally-induced scaly skin. Arch. 

Ethanol and methanol have been used to swell other types of keratinized protein without loss of the a-helieal structure in the presence or after removal of the alcohols (46). Polar lipids such as the ceramides or sphingolipids are soluble in methanol (47). Therefore, extensive extraction periods in methanol could have provided sufficient time to swell the keratinized protein and allow the highly polar lipids entrapped within the protein fibrils to diffuse from the stratum corneum sheet. The resultant protein residue sheets retained the a-keratin conformation throughout the extensive extraction process. 

Ceramide types III and IV were isolated from stratum comeum lipid extracts and separated from cholesterol, free fatty acids, and triglycerides on a silica column (ELSD) in <15min using a 19/1 hexane/ethanol mobile phase [717]. Related compound classes (hydroxy fatty acid ceramide, C2 ceramide, sphingolipid, phyto-sphingosine) were separated on a silica column using a 90/10/1/1 chloroform/ ethanol/triethylamine/formic acid mobile phase. In this case elution was complete in 10 min. 

---