Glycolipids synthesis

The characterization of the first functional cyanobacterial PPTase from Nodularia spumigena SORXQ was reported and its ability to modify carrier proteins from heterocyst glycolipid synthesis and nodularin toxin synthesis was demonstrated. This now opens the door to harness the biotechnological potential of cyanobacterial natural products formation. 

The readily available [77, 78] l,6-di-0-benzoyl-3,4-0-benzylidene-2,5-0-methy-lene-D-mannitol has been converted [79] into the benzyl ether (60), which on periodate oxidation and borohydride reduction gives the methylene acetal (61) which readily gives 1 -O-benzyl-L-glycerol for use in lipid synthesis. The acyl derivative (62) has been used [80] in glycolipid synthesis by glycosidation of the hydroxyl group. 

Despite the small size of glycolipids, their complexity has still driven efforts for synthesis of simpler mimetics in an attempt to identify the minimal structural features required for the biological activity. To this end, many synthetic methods have been adopted in glycolipids synthesis, based on traditional glycosylation... 

Enzyme Catalysis, Chemical Strategies for Glycan Biosynthesis in Mammals Glycosyltransferases, Chemistry of Glycolipids, Synthesis of Glycopeptides and Glycoproteins, Synthesis of... 

Glycolipid synthesis begins on the cytosolic face of the ER (34) with the condensation of a serine residue and a palmityl-CoA to form 3-dehydrosphinganine, which is hy-droxylated at the 4 oxygen, A-acylated, and unsaturated between C4 and C5 in a trans-fashion to form ceramide (Cer)... 

Extracellular Lipid Signals Glycolipids, Synthesis of Lipidomics... 

Sandvig K, Garred O, van Helvoort A, van Meet G, Van Deurs B, Importance of glycolipid synthesis for butyric acid-induced sensitization to Shiga toxin and intracellular sorting of toxin in A431 cells, Mol Biol Cell, 1996 7 1391 -1404. 

Sherwood, J. A., Spitalnik, S. L., Suarez, S. C., Marsh, K. and Howard, R. J. (1988) Plasmodium falciparum glycolipid synthesis constant and variant molecules of isolates and of strains with differing knob and cytoadherence phenotype. J. Protozool. 35 169-172. 

The saccharide structures of the glycosphingolipids do not appear to be closely related to the specific fatty acyl groups present in these lipids and there is no evidence that the saccharide sequence is in any way determined by the aglycone portion of the molecule. To this extent glycolipid synthesis differs from that of glycoproteins, in that nothing equivalent to sequences such as Asn-X-Ser/Thr or other peptide determinants has been identified, or indicated. 

Acetyl CoA can be converted to fatty acyl CoA by one of two routes. One utilises 3-hydroxyacyl CoA dehydrogenase and the other, which proceeds via malonyl CoA, uses acetyl CoA carboxylase. The former route is considered to be reversible and 3-hydroxyacyl CoA dehydrogenase is therefore an enzyme of fatty acid oxidation also. When formed, fatty acyl CoA can be incorporated into other lipids as shown in Figure 2.11. Palmityl CoA, however, has other important utilisation routes leading to the synthesis of sphingomyelins (phospholipid) or ceramide hexosides. The latter represent an important junction of lipid and hexose metabolism and are precursors of the gangliosides which contain hexose, hexosamine, and A -acetylneuraminic acid (referred to briefly under glycolipid synthesis above). 

Changes were noted on glycolipid synthesis effects on synthesis of other glycoconjugates were not measured, f Variable reductions in saturation densitv were observed... 

D. salina cells exposed to tracer amounts of 1 C-16 0 or 1 C-18 1 for as little as 2 min. incorporate sizeable amounts of radioactivity into all classes of lipids (1). The radioactive fatty acids are initially concentrated primarily in neutral lipids and phospholipids, but with the passage of time the label is slowly transferred into glycolipids (Fig. 1). This pattern reflects an initial concentration of the radioactive fatty acid in lipids of extrachloroplastidal membranes, such as the endoplasmic reticulum, followed by a somewhat delayed movement of the isotope into the chloroplast, where glycolipid synthesis is confined. 

Hagelin K. Glycolipids synthesis during the somatic embryogenesis of the carrot, [dissertation]. Buenos Aires University of Buenos Aires, 1990. 

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