A-Acetyl-D-galactosamine

PHA Red kidney bean A-Acetyl-D-galactosamine IV-Acetyl-D-galactosamine... 

ELB Elderberry bark Sialic acid or A-acetyl-D-galactosamine Lactose... 

Using optimized conditions (pentanedione 2 equiv., NaHCOs 4 equiv., H2O-THF 2 1, 90°C, 24 h), Ai-acetyl-o-glucosamine (66) gave the gluco- and manno ketones 69a and 70a in a 4 6 ratio and 83% yield, whereas Af-acetyl-o-mannosa-mine (67) led to the same products in a 3 1 ratio and 40% yield. This poor yield has been explained by the instability of 70a in the reaction mixture. These compounds were easily separated by crystallization of their acetylated derivatives 69b and 70b. Applied to A-acetyl-D-galactosamine (68), the same reaction conditions gave the C-glycosidic ketone 71a, isolated as the acetylated compound 71b (Fig. 12, Table 4). 

Wragg S, Hagen FK, Tabak LA. Kinetic analysis of a recom- 22. binant UDP-A-acetyl-D-galactosamine polypeptide A-acetylga-lactosaminyltransferase. J. Biol. Chem. 1995 270(28) 16947-16954. 

Chondroitin sulfate also consists of a repeating disaccharide of 8-D-glucopyranosyluronic acid-(1 3)-tV-acetyl-D-galactosamine linked p- 4) to the next disaccharide unit, with sulfate groups attached to C-4 or C-6 of the A-acetyl-D-galactosamine residue. It occurs as a major component of cartilage found in the cornea of the eye, the aorta, the skin, and lung tissues, where it is located between fibrous protein molecules. Chondroitin sulfate provides a soft and pliable texture to these tissues [92]. 

The attachment of carbohydrate to nitrogen is invariably by A -acetyl-D-glucosamine and the attachment to oxygen is invariably by A/ -acetyl-D-galactosamine. A -linked carbohydrates are invariably composed of a core pentasaccharide [142] of the following structure ... 

O Figure 15 presents the structures of the three most important and abundant hexosamines found in nature fV-acetyl-D-glucosamine, A-acetyl-D-galactosamine, and IV-acetyl-D-man-nosamine. 

Carriers of the affected gene have a reduced but functional level of this enzyme that normally hydrolyzes a specific bond between an A-acetyl-D-galactosamine and a D-galactose residue in the polar head of the ganglioside. 

Lastly, there is the presumed hydrolysis step to produce A-acetyl-D-galactosamine, which is drawn only for the sake of convenience. There is no evidence for this free species, and it may be used directly as the UDP ester or otherwise modified before its ultimate cellular fate. 

So-called jS-heparin, an anticoagulant isolated from the lung (55) is probably chondroitin sulfate B, for it contains approximately equimolar quantities of A-acetyl-D-galactosamine, a uronic acid (n-iduronic acid- ) and sulfuric acid (14a)- It has about one-third of the anticoagulant activity of the usual heparin ( a-heparin O-... 

T.P. Skelton, L.V, Hooper, V. Srivastava, O. Hindsgaul and J.U. Baenziger, Characterization of a sulfotransferase responsible for the 4-O-sulfation of terminal p-A-acetyl-D-galactosamine on asparagine-linked oligosaccharides of glycoprotein hormones. J. Biol Chem., 1991, 266, 17142-17150. 

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