International Journal of Chemical Research

49-55

Authors: JIE CHAO, JIAN-NING LIU, YAN-CHUN TANG, SHOU-JUN XIAO

We have shown previously that oligonucleotide conjugated hirulog (bivalirudin) has a higher inhibitory activity against thrombin compared with hirulog. The negative charged oligonucleotide was considered to be responsible for the additive activity. To further investigate the related effect of oligonucleotide, the oligonucleotide conjugated hirulog18 was prepared in the present work and the activity of the conjugate against thrombin was measured. Hirulog18, a peptide lack of two N-terminal amino acid residues of hirulog, has little inhibitory activity against thrombin compared with hirulog. The conjugate oligonucleotide-hiruglog18 was successfully synthesized using click chemistry and validated by MALDI-MS and gel electrophoresis. The activity of the conjugate against thrombin was measured by the chromogenic assay using Chromozym TH as substrate. It was found surprisingly that oligonucleotide-hirulog18 had an inhibitory effect better than hirulog18 and hirulog. Strong negative charged heparin was used to study the binding mode between oligonucleotide-hirulog18 and thrombin. The results suggested that the negative charged oligonucleotide could be helpful for the conjugate’s binding to the anion-binding exosite of thrombin via the Coulomb force. The highly inhibitory effect of the oligonucleotide-hirulog18 conjugate against thrombin may present a new strategy to generate a novel class of direct thrombin inhibitors.