Glycoprotein asparagine

Figure 10-6 The pentasaccharide core of all asparagine glycoproteins contains a /9-mannoside linkage.

Asparagine. Glycoproteins containing asparagine linked oligosaccharides are numerous. They comprise all the serum proteins except albumin and many membrane linked glycoproteins. 

Coagulation Factors II, III, VII, IX, X, XI, and Xlla fragments, thrombin, and plasmin are classified as serine proteases because each possesses a serine residue with neighboring histidine and asparagine residues at its enzymatically active site (Table 3). Factors II, VII, IX, and X, Protein C, Protein S, and Protein Z are dependent on the presence of vitamin K [84-80-0] for their formation as biologically functionally active procoagulant glycoproteins. 

FIGURE 9.26 The carbohydrate tnoiedes of glycoproteins may be linked to the protein via (a) serine or threonine residues (in the O-linked saccharides) or (b) asparagine residues (in the N-linked saccharides), (c) N-Linked glycoproteins are of three types high mannose, complex, and hybrid, the latter of which combines structures found in the high mannose and complex saccharides. 

Figure 47-4. Structures of the major types of asparagine-linked oligosaccharides. The boxed area encloses the pentasaccharide core common to all N-linked glycoproteins. (Reproduced, with permission, from Kornfeld R, Kornfeld S Assembly of asparagine-linked oligosaccharides. Annu Rev Biochem 1985 54 631.)...

The major classes of glycoproteins are O-linked (involving an OH of serine or threonine), N-linked (involving the N of the amide group of asparagine), and glycosylphosphatidylinositol (GPi)-linked. 

Fibrinogen (factor I, 340 kDa see Figures 51-1 and 51-4 and Tables 51-1 and 51-2) is a soluble plasma glycoprotein that consists of three nonidentical pairs of polypeptide chains (Aa,Bpy)2 covalently linked by disulfide bonds. The B(3 and y chains contain asparagine-linked complex oligosaccharides. All three... 

The complex oligosaccharides comprising the Y and T antennae of three glycoproteins have been studied by c.d. spectroscopy. Five antennae were studied in all, because two of the proteins have two closely related forms. The c.d. for the three fundamental oligosaccharides are given in Fig. 36. These are asparagine-linked glycopeptides, and the intense, conservative c.d. band that results from the interaction between the two amides has already been discussed in Section III,2. Fig. 36 shows that the c.d. spectra... 

To establish the nature of the carbon-nitrogen bond of the carbohydrate-L-asparagine unit in glycoproteins, treatment of the synthetic derivatives 5 and 211 with hydrochloric acid was first studied in... 

Premier, C., Mach, L., Glossl, J. and Marz, L. (1992) The antigenicity of the carbohydrate moiety of an insect glycoprotein, honey-bee (Apis mellifera) venom phospholipase A2. The role of al,3-fucosylation of the asparagine-bound IV-acetylglucosamine. Bio chemicalJournal 284, 377-380. 

A number of the central themes of current glycoconjugate research can be traced back to studies begun in the Jeanloz laboratory. One prominent example is the elucidation of the sequences of the carbohydrates linked N- or O-glycosylically to asparagine or serine/threonine residues respectively in glycoproteins. Little was... 

Human a-galactosidase is a 100 kDa homodimeric glycoprotein. Each 398 amino acid monomer displays a molecular mass of 45.3 kDa (excluding the glycocomponent) and is glycosylated at three positions (asparagines 108, 161 and 184). After administration (usually every second week by a 40 min infusion), the enzyme is taken up by various body cell types and directed to the lysosomes. This cellular uptake and delivery process appear to be mediated by mannose-... 

Endo-2-acetamido-2-deoxy-)3-D-glucosidase has been used in structural studies of glycopeptides.30 The enzyme cleaves the linkage between the two 2-amino-2-deoxyglucose residues that constitute the chitobiose residue linked to L-asparagine in glycoproteins containing... 

The oligosaccharide sequences just discussed are linked to glycoproteins through the following (generalized) N- and O-linked cores (to asparagine and serine or threonine, respectively). 

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