Phase II Biotransformational Reactions, Essay Example

Phase II biotransformational reactions are essential reactions that serve the important step of detoxification during the metabolism of a drug. This is because these reactions usually entails a small polar endogenous molecule covalently attached to produce compounds that are water soluble. This eliminates pollutants and contaminants in a biological process.

Benzopyrene epoxide detoxification

Epixode molecules are known to react with DNA. As such, it exposes smokers to inherent risks. However, the reaction of Benzopyrene epoxide molecules with glutathione, facilitated by glutathione-S-transferase detoxifies the biological process (van Leeuwen & Hermens, 2007, p. 18). One major contributing factor is the presence of Epoxide hydrolase. It is important to note the reaction with epixode hydrolase takes place after Phase I but does not result in conjugation.

Amino acid conjugation

This process is prevue to xenobiotics which are also carboxylic acids. The carboxylic acid us activated to coenzyme A-thioesters, an amide bond links these product to an amino (taurine, glycine or glutamine). It is important to note that taurine and glycine are used in the synthesis of glycocholate, taurocholate and bile acids (van Leeuwen & Hermens, 2007, p. 137). This can be applied in the alternate urea enzyme pathway therapy. This pathway supplies amino acid conjugates which are used a vehicles to eliminate the excessive nitrogen.

Conjugation of Morphine

Morphine has been found to skip to conjugation, eliminating phase I reactions. This is because its molecule does not necessarily contain functional groups for conjugation as required by Phase I reactions. Since it has two hydroxyl groups, when lucuronic acid conjugates either one or both would lead to sufficient conditions for excretion. It is important to note that of the two single gluronides maintains its pharmacological activity (Prasad, 2010, p. 19).

References

Prasad, J. P. (2010). Conceptual Pharmacology. India: Universities Press.

van Leeuwen, C. J., & Hermens, J. L. (2007). Risk Assessment of Chemicals: An Introduction (Vol. 2nd). Dordrecht: Springer.