Correct disulfide bond linkage is essential for the correct folding of a protein. An analysis to confirm correct disulfide linkages and detect mismatched ones in a therapeutic protein is a key part of ICH Q6B guidelines and FDA “well characterized biological product concept”.

For a large protein such as an IgG antibody, the number of possible linkages between any of two cystine residues is often quite big, e.g. 45 different disulfide bonds can be possibly formed by 10 Cys residues. Therefore, it is often a painstaking and time-consuming process to completely analyze disulfide bond linkages in a therapeutic protein product and to detect (or to rule out) possible low level mismatched disulfide bonds.

At ProtTech, we use a combination of several different mass spectrometric technologies (namely, LC-MS, MALDI-TOF MS, LC-MS/MS) as well as a differential analysis platform to compare the digests from reduced and non-reduced samples of same protein. Our proprietary S2Map software is capable of detecting all possible S-S linkages in a protein and even minor mismatched disulfide bonds, which is often a difficult and time-consuming task even for an experienced scientist.

• Protein Mixture Quantitation & Impurity Analysis

• Peptide Mapping

• Glycosylation Analysis

• Intact Molecular Weight Measurement

• N-terminal and C-terminal Sequencing

• Electrophoresis and Isoelectric Focusing Analysis

• Liquid Chromatographic Analysis

• Colony Selection

• Antibody Epitope Mapping

• Identifying Antibody Molecular Targets

• De Novo Sequencing of mAb

• Software for Characterizing Therapeutic Proteins

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