Mouse anti-Caffeine monoclonal antibody for sELISA. Caffeine is a naturally occurring chemical that is present in tea, cola nuts, guarana and coffee. It is able to stimulate the central nervous system, cardiac muscle, stimulate the respiratory system, act as a diuretic and delay fatigue. The chemical structure for caffeine is 1,3,7-tri methylxanthine. As a modified purine it can act as an inhibitor of enzymes that use compounds containing adenine or guanine as substrates.