The present invention relates to a method for modifying and purifying peptides comprising an immobilizing step, a modification step and a releasing step. In the immobilizing step, a crude linker-tagged peptide L-P is coupled to a solid support yielding an immobilized linker-tagged peptide S-L-P. Subsequently, the immobilized linker-tagged peptide S-L-P is modified with one or more organic molecules yielding an immobilized linker-tagged peptide S-L-mP. Finally, the modified peptide is released via a reduced intermediate RI. The linker molecule is a compound of formula 1, X—Tb—Va-U—Y—Z (1), which can be coupled to a purification resin via the moiety X and to a peptide via the moiety Y under the release of the leaving group Z. T is an optional spacer moiety and V is an optional electron withdrawing moiety. U is an aryl or 5- or 6-membered heteroaryl moiety bound to at least one electron withdrawing moiety V, W or E. The linker is stable under acidic conditions and releases the peptide upon addition of a reducing agent.

The invention relates to a method of isolating an immunoglobulin, comprising the steps of: a) providing a separation matrix comprising multimers of immunoglobulin-binding alkali-stabilized Protein A domains covalently coupled to a porous support, b) contacting a liquid sample comprising an immunoglobulin with the separation matrix, c) washing said separation matrix with a washing liquid, d) eluting the immunoglobulin from the separation matrix with an elution liquid, and e) cleaning the separation matrix with a cleaning liquid,
wherein the alkali-stabilized Protein A domains comprise mutants of a parental Fc-binding domain of Staphylococcus Protein A (SpA), as defined by SEQ ID NO: 51 or SEQ ID NO: 52, wherein the amino acid residues at positions 13 and 44 of SEQ ID NO: 51 or 52 are asparagines and wherein at least the asparagine residue at position 3 of SEQ ID NO: 51 or 52 has been mutated to an amino acid selected from the group consisting of glutamic acid, lysine, tyrosine, threonine, phenylalanine, leucine, isoleucine, tryptophan, methionine, valine, alanine, histidine and arginine.

The invention relates to a method of isolating an immunoglobulin, comprising the steps of: a) providing a separation matrix comprising multimers of immunoglobulin-binding alkali-stabilized Protein A domains covalently coupled to a porous support, b) contacting a liquid sample comprising an immunoglobulin with the separation matrix, c) washing said separation matrix with a washing liquid, d) eluting the immunoglobulin from the separation matrix with an elution liquid, and e) cleaning the separation matrix with a cleaning liquid,
wherein the alkali-stabilized Protein A domains comprise mutants of a parental Fc-binding domain of Staphylococcus Protein A (SpA), as defined by SEQ ID NO: 51 or SEQ ID NO: 52, wherein the amino acid residues at positions 13 and 44 of SEQ ID NO: 51 or 52 are asparagines and wherein at least the asparagine residue at position 3 of SEQ ID NO: 51 or 52 has been mutated to an amino acid selected from the group consisting of glutamic acid, lysine, tyrosine, threonine, phenylalanine, leucine, isoleucine, tryptophan, methionine, valine, alanine, histidine and arginine.

The invention relates to a separation matrix comprising at least 11 mg/ml Fc-binding ligands covalently coupled to a porous support, wherein: a) the ligands comprise multimers of alkali-stabilized Protein A domains, and b) the porous support comprises cross-linked polymer particles having a volume-weighted median diameter (d50, v) of 56-70 micrometers and a dry solids weight of 55-80 mg/ml.

The invention relates to a separation matrix comprising at least 11 mg/ml Fc-binding ligands covalently coupled to a porous support, wherein: a) the ligands comprise multimers of alkali-stabilized Protein A domains, and b) the porous support comprises cross-linked polymer particles having a volume-weighted median diameter (d50, v) of 56-70 micrometers and a dry solids weight of 55-80 mg/ml.

The invention relates to a separation matrix comprising at least 11 mg/ml Fc-binding ligands covalently coupled to a porous support, wherein: a) the ligands comprise multimers of alkali-stabilized Protein A domains, and b) the porous support comprises cross-linked polymer particles having a volume-weighted median diameter (d50,v) of 56-70 micrometers and a dry solids weight of 55-80 mg/ml.

The invention relates to a separation matrix comprising at least 11 mg/ml Fc-binding ligands covalently coupled to a porous support, wherein: a) the ligands comprise multimers of alkali-stabilized Protein A domains, and b) the porous support comprises cross-linked polymer particles having a volume-weighted median diameter (d50,v) of 56-70 micrometers and a dry solids weight of 55-80 mg/ml.

The present invention provides a formulation to link protein to a solid support that comprises one or more proteins, Oligo-dT and one or more non-volatile, water-soluble protein solvents, solutes or combination thereof in an aqueous solution. Further provided is a method of attaching a protein to a surface of a substrate. The formulations provided herein are contacted onto the substrate surface, printed thereon and air dried. The substrate surface is irradiated with UV light to induce thymidine photochemical crosslinking via the thymidine moieties of the Oligo-dT.

The present invention provides a formulation to link protein to a solid support that comprises one or more proteins, Oligo-dT and one or more non-volatile, water-soluble protein solvents, solutes or combination thereof in an aqueous solution. Further provided is a method of attaching a protein to a surface of a substrate. The formulations provided herein are contacted onto the substrate surface, printed thereon and air dried. The substrate surface is irradiated with UV light to induce thymidine photochemical crosslinking via the thymidine moieties of the Oligo-dT.

The present invention concerns the preparation of solutions, particularly for implementing analytical methods, in particular by spectrometry, particularly for producing standard solutions which are useful, for example, for calibrating spectrometers or for implementing diagnostic methods. It allows the implementation of an easy process for preparing such standard solutions.