In which case, it depends on the type of inhibitor. A competitive inhibitor has a structure similar to the substrate, hence would bind to the active site as well, competing with the substrate for the enzyme active sites, decreasing enzymatic activity. A non-competitive inhibitor binds to the allosteric site of the enzyme, causing a structural change in the enzyme active site shape.
There's a difference between the effects of cold-brewed coffee vs. hot-brewed coffee: because different chemical reactions are achieved at higher temperatures, cold-brewed coffee will have a smoother caffeine effect and overall less acidity, which some people experience as part of the kick..
A cup of coffee contains up to 200 mg of caffeine, a cup of tea up to 80 mg tein, and coca cola somewhere between 40 and 70 mg of caffeine. Excessive quantities of coffee can also cause unpleasant side effects such as restlessness, tremors and problems with blood pressure.