Each of the 20 amino acids has a specific side chain, known as an R group, that is also attached to the α carbon. The R groups have a variety of shapes, sizes, charges, and reactivities.

There are 20 amino acids that make up proteins and all have the same basic structure, differing only in the R-group or side chain they have. Amino acids are in an equilibrium between two acids with ...

Amino acids are characterized by their central carbon atom, known as the α-carbon, which is bonded to an amino group (-NH2), a carboxyl group (-COOH), a hydrogen atom, and a variable side chain ...