What are the mechanisms responsible for the failure of protamine to inactivate low-molecular-weight heparin?
The mechanisms responsible for the failure of protamine to inactivate low-molecular-weight heparin are not fully understood. However, studies have suggested that the lower molecular weight of the heparin molecules leads to a decreased binding affinity with protamine, resulting in incomplete neutralization. Additionally, protamine binding to GAGs (glycosaminoglycans) present on the surface of low-molecular-weight heparin molecules also contributes to incomplete neutralization. Other factors associated with the failure of protamine to inactivate low-molecular-weight heparin include the presence of antibodies against protamine, and the presence of other proteins that may interfere with the binding of protamine to the heparin molecules.  