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.
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. 3  Too much could raise your risk of crumbly bones or osteoporosis.  However drinking coffee could give your muscles a boost, experts say.