Phase I metabolism includes which of the following features?

Phase I metabolism includes which of the following features?

• A. Functionalization via Oxidation, Reduction, and Hydrolysis
• B. Uses UDP-Glucuronosyltransferase
• C. Produces Metabolites That Are Always Active
• D. Never Creates Metabolites

Answer: (A)

Phase I metabolism focuses on functionalization: introducing or exposing polar functional groups through oxidation, reduction, and hydrolysis. This often uses enzymes like cytochrome P450s to add or reveal groups such as hydroxyls, amines, or carboxyls, making the molecule more ready for Phase II conjugation and easier to excrete. The option describing functionalization via oxidation, reduction, and hydrolysis captures this essential process, so it’s the best choice. In contrast, UDP-glucuronosyltransferase is part of Phase II, attaching glucuronic acid to substrates for further increase in solubility. Metabolites from Phase I are not always active, and Phase I can indeed produce metabolites, so those statements don’t fit.

Phase I metabolism focuses on functionalization: introducing or exposing polar functional groups through oxidation, reduction, and hydrolysis. This often uses enzymes like cytochrome P450s to add or reveal groups such as hydroxyls, amines, or carboxyls, making the molecule more ready for Phase II conjugation and easier to excrete. The option describing functionalization via oxidation, reduction, and hydrolysis captures this essential process, so it’s the best choice. In contrast, UDP-glucuronosyltransferase is part of Phase II, attaching glucuronic acid to substrates for further increase in solubility. Metabolites from Phase I are not always active, and Phase I can indeed produce metabolites, so those statements don’t fit.