16.4 Amino acid Deamination
Amino acid deamination produces ammonium ions and a carbon skeleton.
Cells can obtain energy from amino acid degradation. The degradation process begins with the oxidative deamination of the amino acid to produce an ammonium ion and a carbon skeleton. For most amino acids, oxidative deamination occurs in two steps (Figure 16.6). First, a transaminase transfers the α-amino group from the amino acid to α-ketoglutarate to form an α-keto acid (the carbon skelcton) and glutamate (Figure 16.6a). Then glutamate dehydrogenase catalyzes the NAD+ -dependent (or NADP+ -dependent) oxidative deamination of glutamate to form α-ketoglutarate, NADH (or NADPH), and ammonium ions (Figure 16.6b).