CYP3A4 is a key enzyme in the human digestive system, where it is required to break down a variety of toxins. The activity of CYP3A4 has been found to be lowered by compounds known as furanocoumarins. Furanocoumarins occur in some fruits, so harmful concentrations of toxins may build up in the human digestive system when fruits containing furanocoumarins are consumed. From the information given, what can be concluded about molecules of the enzyme CYP3A4?
- AThey lower the activation energy of the toxin breakdown reactions.
- BThey bind specifically through the active site to a substrate found in some fruits.
- CThey change permanently when acted upon by furanocoumarin molecules.
- DThey resume normal activity when concentrations of furanocoumarins decrease.