I am wondering what the exact definition of biochemical coupling between two enzymatic reactions is. I know that these two enzymatic reactions have to
share the same intermediate(s)
one is thermodynamically favorable and the other is not.
So the thermodynamically unfavorable reaction can happen when it coupled with the thermodynamically favorable reaction. I just want to confirm that : Do these two enzymes have to be physically associated with each other? Since I do not have any evidence to support the physically interactions between these two enzymes, can I still use the term "biochemical coupling"?