Bivalirudin Bivalirudin Bivalirudin (Angiomax or Angiox, manufactured by The Medicines Company) is a direct thrombin inhibitor (DTI). Chemically, it is a synthetic congener of the naturally occurring drug hirudin (found in the saliva of the medicinal leech "Hirudo medicinalis"). Bivalirudin is a DTI that overcomes many limitations seen with indirect thrombin inhibitors, such as heparin. Bivalirudin is a short, synthetic peptide. It is a potent and highly specific inhibitor of thrombin. It inhibits both circulating and clot-bound thrombin, while also inhibiting thrombin-mediated platelet activation and aggregation. Bivalirudin has a quick onset of action and a short half-life. It does not bind
Peptide bond in peptidyl prolyl isomerases (PPIases), which are naturally occurring enzymes that catalyze the cis-trans isomerization of X-Pro peptide bonds. Conformational protein folding is usually much faster (typically 10–100 ms) than cis-trans isomerization (10–100 s). A nonnative isomer of some peptide groups can disrupt the conformational folding significantly, either slowing it or preventing it from even occurring until the native isomer is reached. However, not all peptide groups have the same effect on folding; nonnative isomers of other peptide groups may not affect folding at all. Due to its resonance stabilization, the peptide bond is relatively unreactive under physiological conditions, even