Amino Acids
Amino acids play central roles both as building blocks of proteins and as intermediates in metabolism. The 20 amino acids that are found within proteins convey a vast array of chemical versatility. The twenty Amino Acids are: Alanine, Arginine, Asparagine, Aspartic acid Cysteine, Glutamic acid, Glutamine, Glycine, Histidine, Isoleucine, Leucine, Lysine, Methionine, Phenylalanine, Proline, Serine, Threonine, Tryptophan, Tyrosine and Valine.
Humans can produce 10 of the 20 amino acids. The other 10 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 Humans 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 of the enzymes required for the biosynthesis of all of the amino acids. (Sources: National Library of Medicine; University of Arizona, Department of Biochemistry and Molecular Biophysics 2007)
Amino Acids – Essential AA:
The essential amino acids for Humans are the following: 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. (Source: National Library of Medicine 2007)
