Proteins and Albumin

Proteins are large polymers of amino acids linked by peptide bonds (Figure 1). The amino acid subunits of proteins are organic molecules that include a carboxylic acid linked through a carbon atom to a primary (or secondary, in proline) amine with the chemical formula H 2 N-CHR-COOH, in which R is a side group that largely determines the chemical properties of the amino acid. The simplest amino acid is glycine, H 2 N-CH 2 -COOH, in which the R side group is a hydrogen atom. Although this chemical template can be modified into an infinite array of molecules based on variations in the R group, only approximately 20 amino acids occur in proteins. The R groups confer acidic, alkaline, polar, or nonpolar properties to the various amino acids.