Glycopep tides

Because of the potential of gaining structural information for reductively [ CJmethylated glycophorins and by pH-titration studies, the pH-titration behavior of reductively, di[ C]methylated glycophorins A and A, and 28 related, reductively di[ C]methylated glycoproteins, glycopep-tides, and peptides in HjO and D2O were investigated. These results are presented in Table II, and Figs. 10 and II. 

Table III gives the titration parameters for the C resonances of the N-terminal mono[ C]methyl labels of a variety of peptides and glycopep-tides related to the N-terminus of glycophorins and A. The titration...

Allylic hydroxycrotyl-oligoethylene glyco-n-alkanoyl (HYCRON) linker 25 was applied to the synthesis of protected peptides and glycopep-tides [31]. HYCRON is stable to both acidic and basic conditions and is compatible with Boc- and Fmoc-based chemistry. The preparation of this novel linker is only two steps from commercially available materials. H YCRON linker can be cleaved under neutral conditions using Pd catalyst (Scheme 9). 

Fig. 1.—Mass Fragmentograms of Partially Methylated Alditol Acetates Obtained from Rat-brain Glycopeptides. [(A) Fraction A glycopeptides, (B) fraction B glycopep-tides, and (C) fraction C glycopeptides. Peak 1, 2,3,4-tri-O-methylfucitol peak 2,...

Otvos et al. (27) adopted the Fmoc-pentafluorophenyl ester methodology and have applied O-deacetylated glycopeptide intermediates (170 and 171) for solid-phase synthesis of glycopeptides. In this way, the A-glycopep-tide (26) H-Gly-L-Lys-L-Ala-L-Tyr-L-Thr-L-Ile-L-Phe-L-... 

Huddleston, M.J. Bean, M.F. Carr, S.A. Colli sional Fragmentation of Glycopep-tides hy ESI LC/MS and LC/MS/MS Methods for Selective Detection of Glyco-peptides in Protein Digests. Amd. Chem. 1993,65, 877-884. 

Multiply resistant coagulase-negative staphylococci are frequently the cause of postoperative endophtalmitis and require the use of a glycopep-tide (e.g. vancomycin). For topical treatment fusidic acid eye gel, tetracycline or chloramphenicol ointment are available, and can be administered 2 t.d. for 7 days. Trachoma should be treated with an oral macrolide (e.g. a single oral dose of 20 mg/kg azithromycin) or doxycyclin for 3 weeks (for moderate to severe cases). Keratitis needs hourly administration of fortified antibiotic eye drops for 2 weeks. Endophtalmitis needs specialist treatment for 6 weeks. 

Vancomycin (Vancocin) is a complex tricyclic glycopep-tide antibiotic produced by Streptomyces orientalis, while teicoplanin (Targocid) is derived from Actino-planes (Actinomyces) teichomyceticus. Teicoplanin has two major components a phosphoglycolipid (Aj) and five chlorine-containing glycopeptides (A2). It is available as an investigational drug. 

Collagen and basement membrane may contain several types of carbohydrate-peptide linkage. They clearly contain linkages in which 5-hydroxy-L-lysine is involved, as already discussed (see p. 436). From the preparations studied were also isolated glycopep-tides in which an asparagine-2-acetamido-2-deoxy-D-glucose linking moiety was present.1Bl-200... 

The niacin vitamers in foods include nicotinic acid and nicotinamide (Fig. 4), which occur in limited quantities in the free form, and their coenzymes, nicotinamide adenine dinucleotide (NAD) and nicotinamide adenine dinucleotide phosphate (NADP) (93,96). The nicotinic acid analog of NAD as well as nicotinamide and nicotinic acid mononucleotides also occur in nature. In addition, niacin occurs as nicotinyl esters bound to polysaccharides, peptides, and glycopep-tides, which are known as niacytin and niacynogens, respectively. In general, the niacin vitamers in cereal grains and other seeds are principally the nicotinic acid forms, whereas those in meat and fish are primarily the nicotinamide forms (94,95). 

Cavalleri B and Parenti F (1992) Antibiotics [glycopep-tides (dalbaheptides)]. Kirk-Othmer Encyclopedia of Chemical Technology, 4th edn, Vol 2. Wiley, New York, pp 995-1018. 

D-Ala-D-Ala peptidase (vanX) Vancomycin- resistant enterococci NA Potentiation of glycopep-tides against vancomycin-resistant enterococci [27-29]... 

L9. Lee, P., and Breckenridge, W. C., Isolation and carbohydrate composition of glycopep-tides of human apo low density lipoprotein from normal and type II hyperlipopro-teinemic subjects. Can. ]. Biochem. 54, 829-832 (1976). 

P, Tabak LA. Characterization of a UDP-GalNAc polypeptide A-acetylgalactosaminyltransferase that displays glycopep-tide A-acetylgalactosaminyltransferase activity. J. Biol. Chem. 26. 1999 274(39) 27867-27874. 

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