-Ketoglutarate Dehydrogenase

-Ketoglutarate dehydrogenase (AKGDH) is an enzyme of the citric acid cycle that catalyzes the decarboxylation of -ketoglutarate.

-Ketoglutarate + NAD+ + CoASH <=> Succinyl-CoA + CO 2 + NADH ( = -33.5 kJ/mol)

The enyzyme uses thiamine pyrophosphate as a coenzyme (Figure 14.14) and is very similar in mechanism of action to the pyruvate dehydrogenase complex (Figure 14.10)

AKGDH exists as a complex, similar to the pyruvate dehydrogenase complex, with three analogous enzyme activities and the same five coenzymes - thiamine pyrophosphate, NAD+, FAD, lipoic acid, and CoASH.

Notably, the AKGDH complex differs from the pyruvate dehydrogenase complex in that the regulatory activities associated with the pyruvate dehydrogenase complex are not present in the -ketoglutarate dehydrogenase complex.

Next enzyme of citric acid cycle / Previous enzyme of citric acid cycle

See also: Citric Acid Cycle, Enzymes of the Citric Acid Cycle, Reaction Picture, Table 14.1,

INTERNET LINKS:

> 1. -Keto Acid Complexes - A Review

> 2. Citric Acid Cycle