Glycine (abbreviated as Gly or G) is the smallest of the 20 amino acids commonly found in proteins.

Glycine has specialized structural properties and is only found in small amounts in most proteins. A notable exception is collagen, which contains about 35% glycine.

References

IUPAC-IUBMB Joint Commission on Biochemical Nomenclature. Nomenclature and Symbolism for Amino Acids and Peptides. Recommendations on Organic & Biochemical Nomenclature, Symbols & Terminology etc. Retrieved on 2007-05-17.