Chemical Structure of Amino Acid

 

Among many substances with the amine structure (N-H3), amino acid is an organic compound with both amino group (-NH₂) and carboxyl group (-COOH) within a single molecule (Image1). Amino acids are generally synthesized from protein hydrolysis. Amino acids bind together to form various types of proteins. Amino acids form a typical dehydration synthesis reaction where the carboxyl group in the front of the chain links with the amino group in the back, releasing a molecule of water. This dehydration synthesis reaction between amino acids is called peptide bond (-CO-NH-) (Image2).

 

Image 2. Peptide bond; a type of dehydration synthesis reaction.

 

[Advertisement] MAGNUM(Q-switched Nd:YAG Laser) – Manufacturer: (www.i-dana.com)]

 

Types of Amino Acids

 

Over 80 types of amino acids have been discovered so far, 20 of which are found in the human body. Plants synthesize amino acids during photosynthesis, whereas, animals cannot produce their own amino acids and need to obtain them through eating plants or other animals. Ironically, plants that are able to synthesize amino acids cannot utilize nitrogen molecules available in the air in this process. Plants absorb amino group, nitrates and nitrites from microorganisms in the soil as ingredients of amino acid synthesis.

 

Natural amino acids have two isomers: dextrorotatory (D) and levorotatory (L), which are mirror images of each other. Glycine, a very simple amino acid, is the only one without isomers, whereas all other amino acids have mirror-image isomers. All amino acids that make up proteins, life’s building blocks, are in the L form. All ingredients of carbohydrates used in life forms are in the D form. For example, glucose is also called dextrose due to its D-glucose form.

 

-To be continued