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.
It can be good for your brain and waistline, but bad for your bones and kidneys: What your daily coffee is really doing to your body. 1  The effects from coffee, good and bad, are largely from the caffeine found naturally in coffee beans. 2  Just one cup can raise the heart rate to 100 beats per minute.