NANP Board Practice Exam 2026 – The All-in-One Guide to Achieving Exam Success!

Taurine is the correct answer as it is the end product of sulfur metabolism in mammals. Sulfur-containing amino acids, primarily methionine and cysteine, undergo several metabolic processes, and through these pathways, taurine is synthesized.

In the body, cysteine is an important precursor for taurine. It is initially oxidized and undergoes various modifications before resulting in taurine. This process involves the transfer of a sulfur atom, contributing to taurine's structure, which is essential for various physiological functions including bile salt formation, antioxidant activity, and modulation of calcium levels in cells.

Other amino acids mentioned do not play the same role in sulfur metabolism. Alanine, glycine, and valine are not products derived specifically from sulfur metabolism, which emphasizes the distinct role of taurine in this biochemical pathway.