An inert tracer: The binding site of a fluorescent dye on the antibody and its effects on Protein A chromatography.

Fluorescently labeled antibodies are widely used to visualize the adsorption process in protein chromatography using confocal laser scanning microscopy (CLSM), but also as a tracer for determination of residence time distribution (RTD) in continuous chromatography. It is assumed that the labeled protein is inert and representative of the unlabeled antibody, ignoring the fact that labeling with a fluorescent dye can change the characteristics of the original molecule. It became evident that the fluorescently labeled antibody has a higher affinity toward protein A resins such as MabSelect Sure.

A Platform for the Generation of Site-Specific Antibody-Drug Conjugates That Allows for Selective Reduction of Engineered Cysteines.

Engineering cysteines at specific sites in antibodies to create well-defined ADCs for the treatment of cancer is a promising approach to increase the therapeutic index and helps to streamline the manufacturing process. Here, we report the development of an screening procedure to select for optimal sites in an antibody to which a hydrophobic linker-drug can be conjugated. Sites were identified inside the cavity that is naturally present in the Fab part of the antibody.

Characterization of highly concentrated antibody solution - A toolbox for the description of protein long-term solution stability.

High protein titers are gaining importance in biopharmaceutical industry. A major challenge in the development of highly concentrated mAb solutions is their long-term stability and often incalculable viscosity. The complexity of the molecule itself, as well as the various molecular interactions, make it difficult to describe their solution behavior.

A peptide methionine sulfoxide reductase highly expressed in photosynthetic tissue in Arabidopsis thaliana can protect the chaperone-like activity of a chloroplast-localized small heat shock protein.

The oxidation of methionine residues in proteins to methionine sulfoxides occurs frequently and protein repair by reduction of the methionine sulfoxides is mediated by an enzyme, peptide methionine sulfoxide reductase (PMSR, EC 1.8.4.