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..
Amounts of caffeine up to 250 milligrams show very few ill effects and may help individuals feel more alert. Doses exceeding 1,000 milligrams may affect sleep and cognitive performance. Side effects of quitting caffeine appear roughly 12 to 24 hours after cessation of coffee consumption and may include headaches, irritability and constipation.