Amino Acid

Definition

Amino acids are compounds containing an amino group, a carboxyl group, a hydrogen atom, and a distinctive side chain, all bonded to a carbon atom, the α-carbon.

Introduction

Amino acids serve as monomer of proteins. Amino acid residues are covalently linked through peptide bond to form a protein. Twenty different amino acids are commonly found in proteins. The first discovered amino acid was asparagine. All amino acids have trivial or common names, in some cases derived from the source from which they were first isolated. Asparagine was first found in asparagus, hence the name asparagine (Vauquelin et al. 1806). All amino acids except glycine are optically active, i.e., they rotate the plane of polarized light.

In an amino acid, if the amino group and carboxylate groups are attached to the same carbon atom, which is called α-carbon, then the amino acid is called α-amino acid. Various α-amino acids differ with respect to the side chain attached to their α-carbon. The general...