13th February 2019

Serine proteases are enzymes that cleave peptide bonds in proteins, in which serine serves as the reactive amino acid at the enzyme’ active site. In humans, they are responsible for coordinating various physiological functions, including digestion, immune response, blood coagulation and reproduction (Hedstrom). The design and development of small molecule inhibitors of proteases have proved difficult due to selectivity problems, and protein inhibitors can be complex in production, expensive and difficult to scale up. An interesting alternative is aptamers that bind with selectivity and also incur minimal cost and complexity in synthesis and modification.

Trypsin is not only a model enzyme in investigations of proteolysis but also a relevant clinical target. This study describes the development and characterisation of nanomolar single-stranded DNA aptamers that inhibit bovine trypsin with no cross reactivity to multiple related enzymes.  Binding of selected aptamers to bovine trypsin was evaluated by ELISA and immobilization assay, inhibition was confirmed by residual activity of the enzymes after pre-incubation with aptamers of interest. To determine specificity porcine pancreatic elastase, human cathepsin G, neutrophil elastase, plasmin and thrombin were tested with the aptamers for inhibition with no impact on activity.  Truncation experiments did show selective loss of activity with bovine thrombin, identifying the areas required for inhibition or aptamer structure stabilization.

Malicki, S., Ksiazek, M., Majewski, P., Pecak, A., Mydel, P., Grudnik, P., Dubin G. (2019).  Development of a novel, high-affinity ssDNA trypsin inhibitor. Journal of Enzyme Inhibition and Medicinal Chemistry, 34(1), pp.638-643

https://www.tandfonline.com/doi/full/10.1080/14756366.2019.1569648

Aptamer Group is currently developing aptamers to a variety of protein, cell, and peptide targets, and can include negative targets and inhibitory testing if similar specificity and activity is required.  If you would like more information on aptamers for your research contact us using the form below.

References:

Hedstrom, L. (Dec 2002). “Serine protease mechanism and specificity”. Chem Rev. 102 (12): 4501–24.