Glycopeptides action

The glycopeptides include vancomycin and teico-planin. They are bactericidal antibiotics. Their mechanism of action is based on inhibition of bacterial cell-wall synthesis by blocking the polymerization of glycopeptides. They do not act from within the peptidoglycan layer, as the beta-lactam antibiotics do, but intracellularly. The indications are mainly restricted to the management of severe or resistant staphylococcal infections, especially those caused by coagulase negative staphylococcal species such as S. epidermidis. 

In examining the action of a-D-mannosidase on ovalbumin and ovalbumin glycopeptides, it is necessary also to consider the in-... 

The first evidence for the presence of an a-D-mannosyl link in ovalbumin glycopeptides was provided by the action of almond emulsin,101,102 although the absence of /3-D-mannosidase from the enzyme preparation was not confirmed until later.103 The presence of 2-acetamido-2-deoxy-/M>glucosidase in emulsin left doubt as to the terminal position of all of the D-mannose released. 

When the ovalbumin was incubated with purified, jack-bean a-D-mannosidase, at least two molecules of D-mannose per molecule were released, suggesting that these residues are a-D-linked in a terminal position. Two glycopeptides having different contents of hexosamine were subjected to the action of purified 2-acetamido-2-deoxy-/ -D-glucosidase, and, in each case, two hexosamine residues per molecule were either inaccessible, or resistant to attack by the enzyme. 

D-Galactose tends to be the next innermost sugar in nonreducing, terminal positions. Thus, about 70-80% of the D-galactose residues of sialic acid-free fetuin,248,319 or of a glycopeptide isolated from it,248 were released by the action of /3-D-galactosidase. Similar results were... 

Teicoplanin is a glycopeptide antibiotic that is very similar to vancomycin in mechanism of action and antibacterial spectrum. Unlike vancomycin, it can be given intramuscularly as well as intravenously. Teicoplanin has a long half-life (45-70 hours), permitting once-daily dosing. This drug is available in Europe but has not been approved for use in the United States. 

Alias, C., Kiger, N, and Jolles, P. 1967. Action of heat on cow x-casein. Heat caseino-glycopeptide. J. Dairy Sci. 50, 1738-1743. 

Allen NE, Nicas TI (2003) Mechanism of Action of Oritavancin and Related Glycopeptide Antibiotics. FEMS Microbiol Rev 26 511... 

Losey HC, Peczuh MW, Chen Z et al (2001) Tandem action of glycosyltransferases in the maturation of vancomycin and teicoplanin aglycones novel glycopeptides. Biochemistry 40 4745 1755... 

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