Figure 24.8. Essential and Nonessential Amino Acids.

Figure 24.8Essential and Nonessential Amino Acids

Some amino acids are nonessential to human beings because they can be biosynthesized in a small number of steps. Those amino acids requiring a large number of steps for their synthesis are essential in the diet because some of the enzymes for these steps have been lost in the course of evolution.

From: Section 24.2, Amino Acids Are Made from Intermediates of the Citric Acid Cycle and Other Major Pathways

Cover of Biochemistry
Biochemistry. 5th edition.
Berg JM, Tymoczko JL, Stryer L.
New York: W H Freeman; 2002.
Copyright © 2002, W. H. Freeman and Company.

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