Abstract

The binding of therapeutic drug candidates to human serum albumin (HSA) and other plasma proteins needs to be monitored and profiled during the development of drug candidates as it affects their adsorption, distribution, metabolism, and excretion (ADME). 

Antisense oligonucleotides are an emerging therapeutic option to treat diseases with known genetic origin. The interaction of these oligonucleotides with proteins like HSA determines their pharmacokinetics (transport and distribution in target tissues) and pharmacodynamic (binding to the mRNA target) properties and hence their eventual pharmacology. Fast characterization of their protein-binding properties requires a simple, robust and reliable method for the quantification of oligonucleotide binding properties to HSA.

In this work, we illustrate the versatility of MST to determine micromolar binding affinities of Cy5-labeled oligonucleotides for HSA. Importantly, these Cy5-labeled oligonucleotides can be used as a tracer to determine the EC50 of an unlabeled oligonucleotide in a competition assay.