Protein Structure
Proteins are complex molecules comprised of a combination of some of the twenty-eight currently known naturally occurring amino acids. Each protein has a unique amino acid sequence and three-dimensional structure and exist as long chains, branched molecules, spheres or helixes (as with DNA). The L-(levorotatory) forms of each amino acid are those found naturally in proteins, while the D-(dextrotatory) form—which can be synthesized but are not part of body proteins— are the mirror images of the naturally occurring ones. Of these naturally occurring amino acids, twenty main L-form amino acids and a few other minor ones are required to build all body proteins.