The enzyme that is responsible for the metabolism of caffeine is produced by the gene CYP1A2 that is code for this enzyme. The change or the variability of the activity of gene and the activity of the enzyme produce by the less activity of gene would affect the clearance of the caffeine from the body and cause disease.
The less efficient enzyme would affect the half life cycle as it will not able to reduce the activation energy which lead to the increase in the half life cycle of the caffeine.
