Essential amino acids

Humans can produce 10 of the 20 amino acids. The others must be supplied in the food. Failure to obtain enough of even 1 of the 10 essential amino acids, those that we cannot make, results in degradation of the body's proteins—muscle and so forth—to obtain the one amino acid that is needed. Unlike fat and starch, the human body does not store excess amino acids for later use—the amino acids must be in the food every day.

The 10 amino acids that we can produce are alanine, asparagine, aspartic acid, cysteine, glutamic acid, glutamine, glycine, proline, serine and tyrosine. Tyrosine is produced from phenylalanine, so if the diet is deficient in phenylalanine, tyrosine will be required as well. The essential amino acids are arginine (required for the young, but not for adults), histidine, isoleucine, leucine, lysine, methionine, phenylalanine, threonine, tryptophan, and valine. These amino acids are required in the diet. Plants, of course, must be able to make all the amino acids. Humans, on the other hand, do not have all the the enzymes required for the biosynthesis of all of the amino acids.

Click to view each of amino acids:

	Alanine		Leucine ---
	Arginine		Lysine
	Asparagine		Methionine
	Aspartic acid		Phenylalanine
	Cysteine		Proline
	Glutamine		Serine
	Glutamic acid		Threonine
	Glycine		Tryptophan
	Histidine		Tyrosine
	Isoleucine ---		Valine

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Structure of Amino Acids
Amino Acid Properties

Classes of Amino Acids
Amino Acid Disorders Screening
Functions and Non-functions in proteins