amino acid


January 23, 2022

Amino acids are the basic building blocks of proteins that make up the body of living things. When proteins are completely hydrolyzed, they are produced together with ammonia. Chemically, it refers to any molecule including an amino group and a carboxy group, and the chemical formula is NH2CHRnCOOH (n1-20). In biochemistry, α (alpha)-amino acids are often referred to simply as amino acids. In α-amino acids, the amino group and the carboxy group are attached to one carbon (called the alpha carbon). Proline, a kind of amino acid, is actually a secondary amine containing a secondary amino group instead of an amino group. Since it performs a function similar to that of a normal amino acid biochemically, proline having a secondary amino group is also classified as an amino acid.


The structure of a general α-amino acid is shown in the figure on the right. Since it contains both an amino group and a carboxyl group, the amino acid exists as an amphoteric ion in neutrality, and the carboxyl group is stabilized in a resonance state. In the structure on the right, R is an acronym for "Residue" or "Remainder", meaning the rest, and represents a side chain, and the type of amino acid is determined depending on what is attached to the side chain. Amino acids are classified into four types: acidic, basic, hydrophilic (polar), and hydrophobic (non-polar) according to the nature of the side chain. Except for glycine, which has only a hydrogen atom in the side chain, all other amino acids have two optical activities, and are divided into D-type and L-type. Most of the amino acids that make up proteins exist in the form of L-amino acids. D-amino acids have also been found in some unusual sea creatures, such as the cone snail. Proteins are made through condensation polymerization, which is a dehydration reaction of amino acids and a peptide bond.


A (basic), B (acidic) and C (uncharged) are hydrophilic and D is hydrophobic. Of the 21 major amino acids, blue is a non-essential amino acid and red is an essential amino acid.

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See also

energy metabolism amino acid synthesis essential amino acids

External Links

Naver Cast - Amino Acids Wikimedia Commons has media related to amino acids.

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