Gene/Protein Disease Symptom Drug Enzyme Compound
Pivot Concepts:   Target Concepts:
Query: EC:3.1.26.9 (ribonuclease)
 6,589 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

Peptide N-glycosidase from Flavobacterium meningosepticum cleaves complex as well as neutral glycoproteins (Plummer, T.H., Jr., Elder, J.H., Alexander, S., Phelan, A.W., and Tarentino, A.L. (1984) J. Biol. Chem. 259, 10700-10704). Examples of neutral glycoprotein substrates include ribonuclease B (one high mannose oligosaccharide chain) and yeast external invertase (nine chains/invertase subunit). The rate of deglycosylation by the glycosidase was greatly enhanced if the glycoprotein substrate was denatured prior to enzyme treatment, from a low of 11-fold for external invertase to a high of 844-fold for ribonuclease B. Peptide N-glycosidase F was unable to cleave the asparaginyl-N-acetylglucosamine bond in endo-beta-N-acetylglucosaminidase H-modified external invertase or ribonuclease B, although that in similarly modified glycopeptide substrate was cleaved. Ribonuclease B was digested sequentially with various exoglycosidases to produce an oligosaccharide chain of varied length. Using the resulting forms of ribonuclease B as substrates for peptide N-glycosidase F, the minimum oligosaccharide chain for cleavage was the di-N-acetyl-chitobiosyl core unit.
 ...
PMID:Requirements of cleavage of high mannose oligosaccharides in glycoproteins by peptide N-glycosidase F. 394 Oct 69

The ability of almond emulsion peptide:N-glycosidase to remove oligosaccharide chains from intact glycoproteins was studied. Protein conformation appeared to be the main factor affecting carbohydrate removal. In the native state the oligosaccharides of ribonuclease B and the Fab mu fragment derived from immunoglobulin M were completely resistant to the enzyme, indicating that the polypeptide chain restricts access to the site of hydrolysis. Heat denaturation in sodium dodecyl sulfate rendered these glycoproteins susceptible to peptide:N-glycosidase, but perturbation with chaotropic salts provided a more gentle approach, which was as effective as detergent-unfolding and more compatible with the stability of the enzyme. Once exposed by the unfolding reagents, the complex oligosaccharides of Fab mu were released more rapidly than the high mannose chains of ribonuclease B, consistent with their preferential release from small glycopeptides (Plummer, T. H., Jr., and Tarentino, A. L. (1981) J. Biol. Chem. 256, 10243-10246).
 ...
PMID:Oligosaccharide accessibility to peptide:N-glycosidase as promoted by protein-unfolding reagents. 710 33