Oxidative Deanimation Components

Now, let's move on to oxidative deamination. Again, let's look at its chemical components.

Here, we are thinking about the amino acid (glutamate), the alpha-keto acid (alpha-ketoglutarate), and the waste byproduct (ammonia).

• Show that the enzyme glutamate dehydrogenase (GDH) is responsible for the oxidative deamination reaction.

So, let's look at their chemical makeup:

• Show glutamate in its glutamic acid state: 5 carbon, 4 oxygen, 1 nitrogen, and 9 hydrogen in its protonated state (glutamic acid) (molecular formula: C5H9NO4).
  • Remember, physiologically, glutamate normally does not exist in the glutamic acid form but rather the unprotonated, glutamate form – but here we show the protonated state of the amino acid for simplicity.

• Next, show alpha-ketoglutarate, which is the product of glutamate after oxygen is added (its oxidized) and the amino group is removed (hence, oxidative de-amination): we see that it's a slightly larger keto acid than oxaloacetate found in the transamination reaction, above.
  • Again, indicate that this is actually the acid form of the molecule for the reasons listed above.

• Show that water provides the oxygen and the hydrogen necessary to oxidize alpha-ketoglutarate and protonate ammonia to ammonium (the non-toxic form of the molecule).
  • We show ammonia in its charged state (as ammonium) because this is how it typically exists at physiologic pH (rather than as uncharged ammonia).