The invention aims to provide an immunoglobulin-binding protein having improved chemical stability, especially stability against alkali. The object can be achieved by improving stability against alkali by substituting an amino acid residue(s) at a particular position(s) in an immunoglobulin-binding domain such as domain C of protein A derived from a bacterium belonging to the genus Staphylococcus, to another/other particular amino acid residue(s).

There is disclosed a relatively simple method to increase the performance of surface localised multi-valent affinity ligands whose target's isoelectric pH differs significantly from the ligand's optimal target-binding pH. This situation can result in ligand binding of target affecting local pH and subsequent binding of more target. Increasing the buffering capacity of the ligand via recombinant or other addition of charge groups to the ligand is expected to partially offset such effects, leading to enhanced binding capacity as well as possible secondary favourable alterations in regard to ligand elution pH, and non-specific surface binding of non-target proteins.

There is disclosed a relatively simple method to increase the performance of surface localised multi-valent affinity ligands whose target's isoelectric pH differs significantly from the ligand's optimal target-binding pH. This situation can result in ligand binding of target affecting local pH and subsequent binding of more target. Increasing the buffering capacity of the ligand via recombinant or other addition of charge groups to the ligand is expected to partially offset such effects, leading to enhanced binding capacity as well as possible secondary favourable alterations in regard to ligand elution pH, and non-specific surface binding of non-target proteins.

The invention provides a sorbent material comprising a PSA that is synthesized via a sol-gel process. The sorbent material enables higher loading of PSA and other functional groups than conventional sorbents. The sorbent material can further encapsulate carbonaceous and/or non-carbonaceous particles that are distributed throughout the sorbent network. The invention also relates to a method of making the sorbent materials.

The present invention relates to a novel polypeptide affinity ligand coupled to solid supports and affinity purification of IgG antibodies. The invention is comprised of (1) the design, generation, and purification of polypeptide ligands, (2) coupling of a polypeptide affinity ligand to a solid support matrix, (3) purification of IgG (polyclonal and monoclonal antibodies), and (4) cleaning and reuse of polypeptide supported solid matrix.

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 present invention relates to a flow-through device comprising at least one separation column wherein a first packing component, which comprises particles of alumina and/or silica, and a second packing component, which comprises a powder of one or more hygroscopic salts are provided. The two packing components may be blended or layered in the device, which may comprise a single tube or a plurality of tubes arranged in a plate format, such as the wells of a multiwall plate or tubes in a rack. In addition, the invention relates to a method for removing one or more matrix components, such as pigments, from a biological sample, by passing said sample across a first packing component, which comprises particles of alumina and/or silica, and a second packing component, which comprises a powder of one or more hygroscopic salts.

The invention relates to strong hydrogen-bond acidic sorbents. The sorbents may be provided in a form that limits or eliminates intramolecular bonding of the hydrogen-bond acidic site between neighboring sorbent molecules, for example, by providing steric groups adjacent to the hydrogen-bond acidic site. The hydrogen bond site may be a phenolic structure based on a bisphenol architecture. The sorbents of the invention may be used in methods for trapping or detecting hazardous chemicals or explosives.

The present invention provides novel chromatographic materials, e.g., for chromatographic separations, processes for their preparation and separations devices containing the chromatographic materials. The preparation of the inorganic/organic hybrid materials of the invention wherein a surrounding material is condensed on a superficially porous hybrid core material will allow for families of different hybrid packing materials to be prepared from a single core hybrid material. Differences in hydrophobicity, ion-exchange capacity, chemical stability, surface charge or silanol activity of the surrounding material may be used for unique chromatographic separations of small molecules, carbohydrates, antibodies, whole proteins, peptides, and/or DNA.