What is an active site and what is its relationship to an enzyme? an active site in an enzyme is the area that breaks the bond in its substrate. E.g. a maltose molecule's glycocide bond is broken by the active site in a maltase enzyme.
The caffeine in a cup of coffee might help your small blood vessels work better. Credit: Â© jogyx / Fotolia. The caffeine in a cup of coffee might help your small blood vessels work better, according to research presented at the American Heart Association's Scientific Sessions 2013.
Regular coffee, under 4 cups per day does not have a direct deleterious effect on the kidneys. However, if you suffer from high blood pressure, caffeine intake does worsen blood pressure control, so you might need to watch that.