Joel Lwande

Date of Award


Degree Name

Master of Science



First Advisor

Dr. David L. Huffman

Second Advisor

Dr. David Reinhold

Third Advisor

Dr. James Kiddle

Access Setting

Masters Thesis-Open Access


The final step of the blood coagulation cascade is catalyzed by thrombin, a serine protease. Like most enzyme activities, thrombin activity encounters inhibition from both direct and indirect inhibitors. A new thrombin inhibitor peptide named theromin was recently isolated from the leech Theromyzon tessulatum, and it is the most potent thrombin inhibitor isolated to date. Theromin is made up of 67 amino acid residues, out of which 16 are cysteines engaged in 8-disulfide bridges.

We synthesized the theromin gene and expressed the protein in Eschericia coli. We purified the recombinant protein and carried out thrombin inhibition assays that enabled us determine the kinetic parameters of the protein. Our studies have resulted in a faster and easier way of obtaining large amounts of the pure recombinant theromin. Our results indicate that both the dimeric and monomeric forms of the recombinant theromin inhibit thrombin activity better than hirudin, a well known thrombin inhibitor. We also show that the monomeric form of theromin has a high tendency to oxidize into its dimeric form.

Included in

Chemistry Commons