New accessory for studies of isotopic (HH)-H-1-H-2 exchange and biomolecular interactions using transmission infrared spectroscopy

摘要

We present here a new accessory for IR transmission measurements of H-1/H-2 exchange, as an ancillary tool for monitoring structural features of biomolecules in aqueous solution. This new accessory results from the combination of two dialysis membranes and a conventional liquid cell having two cylinders containing (H2O)-H-2 buffer. When compared with conventional transmission measurements, carried out either after dissolving lyophilized biomolecules in (H2O)-H-2 or after dialyzing the aqueous solution considered against (H2O)-H-2 buffer, this accessory shows the following advantages: ( 1) controlled measurements over the initial steps of this isotopic exchange and absence of molecular aggregation, and ( 2) smaller sample amounts. This new Fourier transform IR cell can also be used to analyze ligand - biomolecule and drug - cell interactions.