Final answer:
CYP3A4 is a key enzyme involved in drug metabolism in the human body, affecting the metabolism of many pharmaceutical drugs. Other important enzymes include CYP2B6, CYP2D6, and CYP2C19, which are also involved in drug metabolism and are important considerations in drug development due to their polymorphic nature.
Step-by-step explanation:
The enzyme that plays a significant role in drug metabolism in the human body is CYP3A4. This enzyme, along with other cytochrome P450 enzymes such as CYP2B6, CYP2D6, and CYP2C19, are crucial in the metabolism of drugs. These enzymes are found in the liver and are responsible for the in vitro metabolism of drugs in human liver S9 fraction, impacting the safety and efficacy of pharmacological treatments.
In vitro studies, such as the use of specific CYP substrate probes and reaction-phenotyping, help identify which CYP isoforms are involved in the metabolism of drug candidates.
Identifying the contributions of highly polymorphic enzymes like CYP2D6 and CYP2C19 is essential, as polymorphisms can lead to variations in drug efficacy and toxicity among different populations. This understanding is particularly important in the development of pro-drugs, as non-CYP mediated conversion could avoid these pharmacogenomic liabilities.