Edited by Judit OvádiKeywords: Aptamer Thrombin Prothrombin Surface plasmon resonance Equilibrium constant Kinetic constant a b s t r a c t Structural properties determine binding affinities of DNA aptamers specific to thrombin. Our paper is the first to focus on a family of eight G-quadruplex-based aptamers with varied duplex region length (from two to eight base pairs). We have shown that the duplex, which is not the main binding domain, greatly influences the interaction with thrombin and prothrombin. Furthermore, the affinity of an aptamer to thrombin and prothrombin increases (respectively from 2.7 Â 10 À8 M to 5.6 Â 10 À10 M and from 1.8 Â 10 À5 M to 7.1 Â 10 À9 M) with an increase in the number of nucleotide pairs in the duplex region.
DNA aptamer based sorbents are synthesized for binding human IgE. Sorbents effectively removed IgE from human blood plasma. The experimental values of IgE desorption constants were from 11 x 10(-l0) to 1.7 x 10(-10) M depending on the orientation of the aptamer, an insoluble matrix. The sorbents were stable during multiple use. Conditions for sorbent regeneration were picked up. These chromatographic materials can be used for medical and biotechnological applications.