NANP Board Practice Exam

What is the function of Phase I activation in detoxification?

1. Activates bile acids

2. Biotransforms glycine

3. Produces an active site on the toxin using oxygen

4. Synthesizes glutathione

The correct answer is: Activates bile acids

The correct function of Phase I activation in detoxification involves the process of introducing or exposing functional groups on a toxin to make it more reactive, and this is often done using oxygen. This step is crucial, as it transforms the toxins into more polar metabolites, which can then be further processed in Phase II for excretion. Phase I reactions typically involve enzymes such as cytochrome P450s, which oxidize substances, adding oxygen to the toxin and facilitating its conversion into a more biochemically manageable form. This transformation generates an active site on the toxin, making it more amenable to conjugation in Phase II. The other choices do not accurately represent the primary function of Phase I detoxification. While bile acids and glutathione play important roles in the detoxification processes, they are more related to Phase II and other metabolic pathways rather than being specific outputs of Phase I activation. Biotransformation of glycine also falls outside the scope of Phase I, which is primarily focused on modifications that prepare toxins for further processing rather than handling amino acid conjugation.