【各選項詳解】評論
(A) Serine and threonine can be directly deaminated to produce NH4+. Deamination is the process of removing the amino group (-NH2) from an amino acid. When serine and threonine are deaminated, they are converted into pyruvate and 2-ketobutyrate, respectively, and an NH4+ ion is produced as a byproduct. Other amino acids, such as asparagine, valine, and proline, cannot be directly deaminated.