Abstract: A glycopeptide of the formula A1-A2-A3-A4-A5-A6-A7, in which each dash represents a covalent bond; wherein A1 comprises a modified or unmodified ?-amino acid residue, alkyl, aryl, aralkyl, alkanoyl, aroyl, aralkanoyl, heterocyclic, heterocyclic-carbonyl, heterocyclic-alkyl, heterocyclic-alkyl-carbonyl, alkylsulfonyl, arylsulfonyl, guanidinyl, carbamoyl, or xanthyl; wherein each of A2 to A7 comprises a modified or unmodified ?-amino acid residue, whereby (i) A1 is linked to an amino group on A2, (ii) each of A2, A4 and A6 bears an aromatic side chain, which aromatic side chains are cross-linked together by two or more covalent bonds, and (iii) A7 bears a terminal carboxyl, ester, amide, or N-substituted amide group; and wherein one or more of A1 to A7 is linked via a glycosidic bond to one or more glycosidic groups each having one or more sugar residues, at least one of the sugar residues bearing one or more substituents of the formula YXR, N+(R1)=CR2R3, N=PR1R2R3, N+R1R2R3 or P+R1R2R3 in which Y is a singl

Abstract: A simple and efficient method of preparing a sample in the measurement according to matrix-assisted laser desorption/ionization mass spectrometry (MALDI-MS) capable of inhibiting any ion suppression by impurities, such as inorganic salts and surfactants, contained in the sample. An analyte and matrix molecules are co-crystallized in the presence of porous microparticles. Preferably, this co-crystallization is carried out by bringing the analyte, matrix molecules and porous microparticles into contact with each other on a target plate and thereafter drying the mixture. The porous microparticles consist of an ion exchanger having an average particle diameter of not more than 50 ?m, preferably a strongly basic anion exchanger.

Abstract: Methods for preparing a glycopeptide are disclosed. The methods comprise the steps of selecting a protected glycopeptide of the formula A1-A2-A3-A4-A5-A6-A7, wherein the groups A1 to A7 comprise the heptapeptide structure of naturally occurring vancomycin; at least A4 is linked to a glycosidic group which has a hexose residue linked to A4; and the protected glycopeptide has no free amino or carboxyl groups and has a free primary hydroxyl group only at the 6-position of said hexose residue. The protected glycopeptide is contacted with a compound of the formula ArSO2G where Ar is an aryl group and G is a leaving group under conditions effective to allow reaction of said free primary hydroxyl group to form a glycopeptide sulfonate ester; and the glycopeptide sulfonate ester is contacted with a nucleophile under conditions effective to allow displacement of a sulfonate group to produce a substituted glycopeptide.

Abstract: A glycopeptide of the formula A1-A2-A3-A4-A5-A6-A7, in which each dash represents a covalent bond; wherein A1 comprises a modified or unmodified ?-amino acid residue, alkyl, aryl, aralkyl, alkanoyl, aroyl, aralkanoyl, heterocyclic, heterocyclic-carbonyl, heterocyclic-alkyl, heterocyclic-alkyl-carbonyl, alkylsulfonyl, arylsulfonyl, guanidinyl, carbamoyl, or xanthyl; wherein each of A2 to A7 comprises a modified or unmodified ?-amino acid residue, whereby (i) A1 is linked to an amino group on A2, (ii) each of A2, A4 and A6 bears an aromatic side chain, which aromatic side chains are cross-linked together by two or more covalent bonds, and (iii) A7 bears a terminal carboxyl, ester, amide, or N-substituted amide group; and wherein one or more of A1 to A7 is linked via a glycosidic bond to one or more glycosidic groups each having one or more sugar residues, at least one of the sugar residues bearing one or more substituents of the formula YXR, N+(R1)?CR2R3, N?PR1R2R3, N+R1R2R3 or P+R1R2R3 in which Y is a single

Abstract: A glycopeptide of the formula A1-A2-A3-A4-A5-A6-A7, in which each dash represents a covalent bond; wherein A1 comprises a modified or unmodified &agr;-amino acid residue, alkyl, aryl, aralkyl, alkanoyl, aroyl, aralkanoyl, heterocyclic, heterocyclic-carbonyl, heterocyclic-alkyl, heterocyclic-alkyl-carbonyl, alkylsulfonyl, arylsulfonyl, guanidinyl, carbamoyl, or xanthyl; wherein each of A2 to A7 comprises a modified or unmodified &agr;-amino acid residue, whereby (i) A1 is linked to an amino group on A2, (ii) each of A2, A4 and A6 bears an aromatic side chain, which aromatic side chains are cross-linked together by two or more covalent bonds, and (iii) A7 bears a terminal carboxyl, ester, amide, or N-substituted amide group;

Abstract: A glycopeptide of the formula A1—A2—A3—A4—A5—A6—A7, in which each dash represents a covalent bond; wherein A1 comprises a modified or unmodified &agr;-amino acid residue, alkyl, aryl, aralkyl, alkanoyl, aroyl, aralkanoyl, heterocyclic, heterocyclic-carbonyl, heterocyclic-alkyl, heterocyclic-alkyl-carbonyl, alkylsulfonyl, arylsulfonyl, guanidinyl, carbamoyl, or xanthyl; wherein each of A2 to A7 comprises a modified or unmodified &agr;-amino acid residue, whereby (i) A1 is linked to an amino group on A2, (ii) each of A2, A4 and A6 bears an aromatic side chain, which aromatic side chains are cross-linked together by two or more covalent bonds, and (iii) A7 bears a terminal carboxyl, ester, amide, or N-substituted amide group; and wherein one or more of A1 to A7 is linked via a glycosidic bond to one or more glycosidic groups each having one or more sugar residues, at least one of the sugar residues bearing one or more substituents of the formula YXR, N+(R1)═CR2R3, N