Use of chelating agents to improve the resolution and consistency of cation-exchange chromatography of monoclonal antibodies.

Analytical cation-exchange chromatography (CEX) is widely used to profile the charge heterogeneity of therapeutic monoclonal antibodies (mAbs). However, the consistency of CEX profiles of a mAb can be significantly reduced by metal ion impurities from sample, mobile phase or leachates from the stainless steel components of the pumping system. In this work, we have developed a new CEX method that dynamically removes metal ions during sample analysis by incorporating the use of chelating agents (1-5mM) in HPLC mobile phases.

Proteolytic DNA for mapping protein-DNA interactions.

We describe a technique to determine sites on proteins involved in protein-DNA interactions. DNA was synthesized via polymerase chain reaction (PCR) to produce four polynucleotide products with phosphorothioate nucleotides at the A, T, G, or C residues. Limited conjugation with the chemical protease FeBABE results in the surface of DNA being randomly labeled at the phosphorothioate sites with this protein-cleaving reagent.

Electrophilic chelating agents for irreversible binding of metal chelates to engineered antibodies.

Radiolabeled monoclonal antibodies are widely used in the detection and treatment of cancer. However, several problems still prevent full clinical exploitation of these reagents. Low tumor/background ratios in radioimmunoscintigraphy and high background radioactivity in therapy are the foremost among these.