Glycopeptides ribonuclease

Witte K, Sears P, Martin R, Wong CH. Enzymatic glycoprotein synthesis Preparation of ribonuclease glycoforms via enzymatic glycopeptide condensation and glycosylation. J. Am. Chem. Soc. 1997 119 2114-2118. 

Figure 2. Glycopeptides from pronase digestion of ribonuclease B. Two series are observed corresponding to the dipeptide RN and single amino acid N.

Syntheses have been reported for a number of glycopeptide derivatives containing the JV -(2-acetamido-2-deoxy-/J-D-glucopyranosyl) hydrogen L-asparagin-ate linkage and having the amino-acid sequences 32-34, 33-35, 33-37, and 33-38 of bovine ribonuclease. ... 

Oligosaccharides from glycopeptides by hydarazinolyses Derivatization 2-pyridylamine dimethylamine/borane D FI Aex = 320 nm Aem = 380 nm C Fused silica (60 cm x 50 pm i.d.) polyimine coated E 100 mmol 1 phosphate, pH 2.5 200 mmol I borate V 20 kV Glycopeptides obtained by trypsine digestion of human transferrin, serum fetuin, human immunoglobulin, bovine, spleen ribonuclease, yeast invertase... 

Fig. 2. The suggested structure for the glycopeptide isolated from ribonuclease B by Tarentino et al. (1970). The possibility has not been eliminated that some a-mannosidase-sensitive mannose residues could be attached at positions other than shown, e.g., on the GlcNAc residue attached to Asn.

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