L Amino Acid Definition:

Amino acids with Fischer projections that resemble the Fischer projections of l sugars.

L Amino Acid Explained:

The amino group is always on the left side of the alpha carbon. In organic chemistry, this stereochemistry is referred to as L (for Levo, meaning left). Thus, the amino acids found in proteins are L‐alpha amino acids. (Biochemists, being creatures of habit, usually do not refer to amino acid stereochemistry in the R and S nomenclature.) A few D‐amino acids are found in nature, although not in cellular proteins. (The D comes from Dextro, meaning right.) For example, some peptide antibiotics, such as bacitracin, contain D‐amino acids.