Name Lysine Arginine Histidine Aspartate Glutamate Structure 1-Let Abbr 3-Let Abbr Class Special Props рка Side Chain

Amino acids are organic compounds that form the building blocks of proteins in cells. The structure of an amino acid consists of a central alpha carbon atom attached to functional groups including a basic amino group (NH₂), an acidic carboxyl group (COOH) and a organic side chain R group (differing for each amino acid). Amino acids are basically amphoteric in nature which means that they can exist either as an acid or as a base whereas at physiological pH they are neutral in charge. There are 20 standard amino acids classified on the basis of the side chain R group, their polarity, charge, location of functional groups, ionization, etc. Additionally, two other amino acids (Selenocysteine and pyrrolysine) have been discovered to be incorporated under special translation mechanisms. Based on chirality almost all standard amino acids occurring in proteins exist as L-form (Laevorotatory or left-handed) rather than D-form (Dextrorotatory or right-handed). The general nomenclature of amino acids is given by IUPAC-IUBMB Joint Commission on Biochemical Nomenclature.