Principles of Biochemistry Volume 2 - A. Lehninger 1985
Bioenergetics and Metabolism
Oxidative Degradation of Amino Acids. The Urea Cycle
Oxaloacetate Pathway
The carbon skeletons of asparagine and aspartic acid ultimately enter The Citric Acid Cycle via oxaloacetate (Fig. 19-4). The enzyme asparaginase catalyzes the Hydrolysis of asparagine to yield aspartate
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The amino group of aspartate is then transferred to α-ketoglutarate in a Transamination reaction, producing glutamate
The remaining carbon Skeleton of aspartate, in the form of oxaloacetate, enters The Citric Acid cycle.
Thus, we have now seen how the 20 common Amino Acids are degraded—following deamination—through dehydrogenation, decarboxylation, and other conversions into five familiar metabolites, via which portions of their carbon skeletons can enter the citric acid cycle. Here these fragments are fully oxidized to carbon dioxide and Water. During electron transfer in Oxidative Phosphorylation, ATP is synthesized. In this way, amino acids contribute to the overall Energy supply of the Organism.
Last update: 06/08/2026
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