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Encyclopedia entry: amino acids
- Article from:
- The Oxford Companion to the Body
- Author:
Copyright© The Oxford Companion to the Body 2001, originally published by Oxford University Press 2001. (Hide copyright information)
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amino acids
are the building blocks of
proteins
. They are so named because all have a basic amino group (-NH
2
) and an acidic carboxyl group (-COOH).
Peptides
, polypeptides, and proteins are formed from strings of amino acids joined together by the formation of peptide bonds. All proteins are formed from combinations of only 20 different amino acids, whether the proteins derive from bacteria or from man.
Amino acids are described as essential or non-essential. The non-essential ones can be synthesized in the body but the essential amino acids are those which must be present in the diet (phenylalanine, valine, tryptophan, threonine, lysine, leucine, isoleucine, and methionine). If any one of ...