Carbohydrate chain

Ketose (Section 25 1) A carbohydrate that contains a ketone carbonyl group in its open chain form Kiliam-Fischer synthesis (Section 25 20) A synthetic method for carbohydrate chain extension The new carbon-carbon bond IS formed by converting an aldose to its cyanohydnn Reduction of the cyano group to an aldehyde function com pletes the synthesis... 

Fig. 3. Fluman LH, FSH, and TSH a suburnt [69431-84-1]. Amino acid numbering is relative to maximum homology between species (48). Note the 4 amino acid deletion in human a suburnt between positions 6 and 9. Consensus glycosylation sites are at Asn-56 and 82. GHO = carbohydrate chain.

Fig. 3. Human CG, hLH, and equine CG (eCG) P-subunits. Amino acid numbeiing is relative to maximum homology between the three subunits. Consensus glycosylation sites ate at Asn-13 and 30. = same amino acid as hCG/3. Underlined Asn residues indicate attachment of N-linked carbohydrate chains. Serines at positions 121, 127, 132, and 138 of hCGP are underlined to indicate sites of O-linked carbohydrate attachment. Residues 115—118,...

If substitution at the terminal carbon atom of the carbohydrate chain creates a chiral centre, the stereochemistry is indicated by the R.S system. 

Where the new bridge is attached to oxygen (or a replacement heteroatom, e.g. nitrogen in an amino sugar) already indicated in the name of the unbridged carbohydrate, the bivalent substituent prefix denotes substitution at two heteroatoms as outlined in 2-Carb-24.1 and 2-Carb-25 [method (b)]. Heteroatoms not directly bonded to the carbohydrate chain are regarded as part of the bridge. 

Where the new bridge is attached through C-C bonds to the carbohydrate chain, the bridge prefix denotes a double C-substitution. Procedures are as outlined in 2-Carb-16. 

Nevertheless, the isolation of these metabolites was interesting in two respects. First, the structure of the thiazole glycol stimulated the research of functionalized carbohydrate chains as precursors of thiazole. Second, the thiazolecar-boxylic acid 40 can be secreted by derepressed cells in relatively high amounts, 0.24 nmol per mg of dried cells, which is nearly half the amount of synthesized thiamine. The presence of this free thiazolic derivative in the cells contrasts with... 

Glycoproteins are widely distributed proteins— with diverse functions—that contain one or more covalently linked carbohydrate chains. 

Coelenterates and Echinoderms. Coelenterate and echinoderm toxins range from small molecular weight amines, to sterols, to large complex carbohydrate chains, to proteins of over 100,000 daltons. Molecular size sometimes reflects taxonomy, e.g., sea anemones (Actiniaria) all possess toxic polypeptides varying in size from 3,000 to 10,000 daltons while jellyfish contain toxic proteins (ca. 100,000 daltons). Carotenoids have been isolated from Asterias species (starfish), Echinoidea (sea urchins), and Anthozoans such as Actiniaria (sea anemones) and the corals. These are sometimes complexed with sterols (J5). 

F.a.b.-m.s. has contributed to a detailed analysis of the high-mannose carbohydrate chains of prostaglandin endoperoxide synthase from sheep. Oligosaccharides released by hydrazinolysis were analyzed after N-re-acetylation and reduction. The f.a.b. data defined the compositions of the oligosaccharides, and showed that hydrazinolysis had effected a partial fission of the chitobiose core. 

Initial MALDI-TOF MS indicates that only two of the four bean sites have carbohydrate chains attached (data not shown). 

In the present paper we describe a contribution of the neutral carbohydrate chains in PG-lc for expression of its anti-complementary and mitogenic activities. 

Glycoproteins1 are macromolecules containing one carbohydrate chain (or several) covalently linked to a protein backbone. They include... 

Kubelka, V., Altmann, F., Staudacher, E., Tretter, V., Marz, L., Hard, K., Kamerling, J.P. and Vliegenthart, F.G. (1993) Primary structure of the A-linked carbohydrate chains from honeybee venom phospholipase A2. European Journal of Biochemistry 213, 1193—1204. 

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