ANGIOGRAPHY CONTRAST AGENTS INTERACT WITH SERINE PROTEINASES - THE MOLECULAR-STRUCTURE OF THE MODEL SYSTEM ELASTASE IOHEXOL

Pancreatic elastase was co-crystallised with iohexol, a tri-iodo benze nic contrast agent used in angiography analyses. The X-ray analysis of the complex reveals the presence of three molecules of iohexol associ ated with the proteinase with low occupancy factors. Two iohexol molec ules are located in and near the active site of the enzyme and provide a model for explaining the inhibition of the hemostatic system, one o f the major and inconvenient side effect associated with these chemica ls.