Attention:

Certain features of Sigma-Aldrich.com will be down for maintenance the evening of Friday August 18th starting at 8:00 pm CDT until Saturday August 19th at 12:01 pm CDT.   Please note that you still have telephone and email access to our local offices. We apologize for any inconvenience.

Amino Acids

Amino Acids Reference Chart

Amino Acids (AAs) is a group of organic molecules, comprising of a basic amino group (-NH2), an acidic carboxyl group (-COOH), and an organic R group (or side chain) which is unique to each amino acid. Amino acids are building blocks of proteins, as well as the intermediates in metabolism. The amino and the carboxyl groups of amino acids react to form a covalent amide linkage, called as peptide bond. This feature of amino acids allow them to polymerize to form peptides as well as proteins.There are 20 amino acids in one’s body proteins. Amino acids can be classified into three groups essential AAs, non-essential AAs and conditional AAs. They can also be classified as non-polar or hydrophobic, neutral but polar, acidic and basic AAs. All amino acids are chiral molecules except glycine, and are amphoteric in nature.