Now the majority of the time when this binding takes place between the Irreversible inhibitor and the enzyme, the binding is via covalent bonds. But sometimes we can also have non Covalent bonds. So some inhibitors will bind to enzymes very tightly, either by covalent or non Covalent means. And once bound, they will not dissociate very easily from the enzyme. And these inhibitors are known as Irreversible inhibitors. They have a very high affinity for the enzyme.