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.