Amino Acids Are Required in the Diet for Good Nutrition

Many Amino Acids Are Required in the Diet for Good Nutrition 

The inability of mammals to synthesize all of the amino acids they require has led to the classification of amino acids as essential and nonessential. Conceptually this distinction seems clear. Practically speaking, it turns out to be more complex to designate essential amino acids. An essential amino acid, in this classification, means one that must be supplied in the diet if the organism is to maintain a positive nitrogen balance. As we will see, the absence of a de novo pathway for the biosynthesis of an amino acid does 

The results in table 22.1 indicate that given 19 other amino acids, the particular amino acid can be formed either 

Synthesis of arginine by the salvage pathway found in vertebrates and by the de novo pathway found in plants and bacteria. The final steps from ornithine to arginine are also part of the urea cycle (see fig. 22.7). 

Essential Amino Acids Must Be Obtained by Degradation of Ingested Proteins 

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Humans and Rodents Synthesize Less Than Half of the Amino Acids They Need for Protein Synthesis Many Amino Acids Are Required in the Diet for Good Nutrition... 

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