But unlike in the sequential case in which these two molecules, A and B, have to bind into the active side together for that reaction to take place, in this particular case, in a double displacement reaction, what happens is first, one of these molecules, let's say A binds onto the active side of that enzyme and a group on A is transferred into that enzymes active side and that modifies that enzyme and it also transforms our reactant A into, let's say product C. And then product C is released. And once product C is released, we now have that modified enzyme. And only now can the second substrate B actually bind onto the active site of that modified enzyme to form an intermediate between the enzyme and that reactant B. And now that group that was transferred into the active site of the enzyme by A is transferred onto this reactant B and that transforms that reactant B into product D and that basically ultimately releases that product D from the active site of the enzyme. And now the enzyme, the original enzyme in its original form is released by that reaction. So the major difference between the sequential reaction and the double displacement reaction is for the reaction to actually take place in a sequential reaction, both have to be bound onto the active side.