A Structural Model for the Interaction of Haem with Unsaturated Fatty Acids Explaining Its Quasi-lipoxygenase Activity. Quantum Chemical Calculations

The quasi-lipoxygenase activity of haemoglobin differs in many respects from the well-known haemin-catalyzed lipid peroxidation (1-4), especially in its high substrate specificity for unsaturated fatty acids containing one 1,4-pentadiene system (dienoic fatty acids). In this report a structural model for the fatty acid haem interaction based on quantum-chemical calculations is presented which show that only dienoic fatty acids are bound to the haem in such a way that the initial hydrogen abstraction that is necessary for the over-all reaction, is favoured sterically and energetically.