Ceramides characterization

Lipid phosphate phosphohydrolases (LPPs), formerly called type 2 phosphatidate phosphohydrolases (PAP-2), catalyse the dephosphorylation of bioactive phospholipids (phosphatidic acid, ceramide-1-phosphate) and lysophospholipids (lysophosphatidic acid, sphingosine-1-phosphate). The substrate selectivity of individual LPPs is broad in contrast to the related sphingosine-1-phosphate phosphatase. LPPs are characterized by a lack of requirement for Mg2+ and insensitivity to N-ethylmaleimide. Three subtypes (LPP-1, LPP-2, LPP-3) have been identified in mammals. These enzymes have six putative transmembrane domains and three highly conserved domains that are characteristic of a phosphatase superfamily. Whether LPPs cleave extracellular mediators or rather have an influence on intracellular lipid phosphate concentrations is still a matter of debate. 

Very recently, two yeast (5. cerevisiae) alkaline ceramidases, phytoceramidase (YPClp) and dihydroceramidase (YDClp), were cloned and partially characterized by Mao et al (2000a, b). YPClp was cloned as a high copy suppressor of the growth inhibition by FBI as it has fumoitisin resistant ceramide synthase activity. The second alkaline ceramidase, YDClp was identified by sequence homology to YPClp. 

Biochemical characterization of the reverse activity of rat brain ceramidase A CoA-independent and fumonisin B1 insensitive ceramide synthase. J. Biol. Chem. published February 8, 2001 as 10.1074/jbc.M009331200. 

Purification and characterization of ceramide-activated protein phosphatases. Biochemistry 37 11232-11238. 

Michel, C., Van Echten-Deckert, G., Rother, J., Sandhoff, K., Wang, E, and Merrill, A.H Jr., 1997, Characterization of Ceramide Synthesis. A Dihydroceramide desaturase intoduces the 4,5-trans-double bond of sphingosine at the level of dihydroceramide. /. Biol. Chem. 111-. 22432-22437. 

Tani, M., Okino, N., Mitsutake, S., Tanigawa, T, Izu, H., and Ito, M., 2000a, Purification and characterization of a neutral ceramidase from mouse fiver. A single protein catalyzes the reversible reaction in which ceramide is both hydrolyzed and synthesized. J. Biol. Chem. 275 3462-3468. 

Gangliosides are a class of glycosphingolipid characterized by the presence of one or more sialic acid residues. They are located in the cell membranes, particularly in the plasma membrane, of almost all cell types. They are anchored in the membranes through their ceramide moiety and have the polar sugar-containing group in the extracytoplasmic side. They are particularly abundant in the nervous system where their expression pattern is modulated during development. 

Colsch B, Afonso C, Popa I, Portoukalian J, Fournier F, Tabet JC, Baumann N. 2004. Characterization of the ceramide moieties of sphingoglycolipids from mouse brain by ESI-MS/MS identification of ceramides containing sphingadienine. J Lipid Res 45 281. 

Kolesnick, R.N. Hemer, M.R. Characterization of a ceramide kinase activity from human leukemia (HL-60) cells. Separation from diacylglycerol kinase activity. J. Biol. Chem., 265, 18803-18808 (1990)... 

Sugiura, M. Kono, K. Liu, H. Shimizugawa, T. Minekura, H. Spiegel, S. Kohama, T. Ceramide kinase, a novel lipid kinase. Molecular cloning and functional characterization. J. Biol. Chem., 277, 23294-23300 (2002)... 

Fig. 21.6. Glycosphingolipids of Pseudophyllida. Glycolipids of Spirometra erinacei were analysed by Kawakami et al. (1995) [1], (1993) [2] and (1996) [3], Glycolipids of S. mansonoides were analysed by Singh et al. (1987) [4]. Glycolipids of D. balaenopterae and D. hottai were characterized by Kawakami et al. (1997) [5] and Iriko et al. (2002) [6], respectively. Gal((S1 -6)-units are marked by boxes. Cer, ceramide.

Fig. 21.7. Glycosphingolipids and protein glycosylation of Cyclophyllida. Glycolipids of E. multilocularis were analysed by Persat et al. (1990) [1] and (1992) [2]. Glycolipids of T. crassiceps and M. coturnix were characterized by Dennis et al. (1992) [3] and Nishimura etal. (1991) [4], respectively. The major glycolipid of T. solium was analysed by Lopez-Marin etal. (2002) [5], Cer, ceramide. A/-glycans of E. granulosus and O-glycans of . multilocularis were described by Khoo etal. (1997c) [6] and Hulsmeier et al. (2002) [7], respectively. Possible Gala1-4)Gal1- structural elements are boxed.

A quantitative HPLC method for the analysis of sphingolipids as their perbenzoyl derivatives was first developed for ceramides (5). Ceramides can be conveniently derivatized with benzoic anhydride in pyridine (3 hrs at 110°C) and the products formed have been utilized for the quantitative analysis of NFA and HFA ceramides in normal and Farber s disease tissue. Iwamori and Moser also utilized this procedure for the analysis of ceramides in Farber s disease urine (6). More recently Iwamori and Moser (7) established that the ceramide derivatives formed by reaction with benzoyl chloride or benzoic anhydride are analogous to those formed with cerebrosides. They also characterized the behavior... 

There are several genetic skin diseases with known defects in the lipid metabolism. Atopic dermatitis, lamellar ichthyosis, and psoriasis have been the most widely studied with respect to epidermal barrier function and alterations in the lipid profile. Deviations in the lipid profile have been linked with an impaired stratum corneum barrier function. Atopic dermatitis is characterized by inflammatory, dry and easily irritable skin, and overall reduced ceramide levels in the stratum corneum [58-60]. In particular a significant decrease in the ceramide 1 level is observed, whereas the levels of oleate that is esterified to ceramide 1 are elevated [59]. Both aberrations may be responsible for the reduced order of the lamellar phases as observed with freeze fracture electron microscopy [61]. It has further been established that, in comparison to healthy stratum corneum, the fraction of lipids forming a hexagonal packing is increased [61]. A recent study reveals that the level of free fatty acids... 

---