Glycine is the simplest stable amino acid, characterized by having a single hydrogen atom as its side chain. It is one of the 20 proteinogenic amino acids used to build proteins in the body and is unique among them as the only achiral amino acid, meaning it is not optically active
. It is encoded in the genetic code by all codons starting with "GG" (GGU, GGC, GGA, GGG)
. Glycine plays several important roles in the body:
- Protein building: It is a precursor to proteins and is especially abundant in collagen, where it makes up about 35% of the amino acids due to its role in collagen's helix structure
- Neurotransmitter: Glycine acts as an inhibitory neurotransmitter in the central nervous system, particularly in the spinal cord, brainstem, and retina, where it helps regulate nerve signals
- Biosynthesis: It is involved in the synthesis of important biomolecules like creatine, purines, and porphyrins (precursors to heme)
- Health benefits: Glycine contributes to the production of glutathione, a powerful antioxidant that protects cells from oxidative damage. It may also support heart and liver health, improve sleep quality, and reduce muscle loss
- Detoxification: Glycine participates in detoxification pathways by conjugating with toxins such as benzoate to form more water-soluble compounds for excretion
The body can synthesize glycine on its own, but it is also obtained from dietary sources such as meat, fish, dairy, and legumes
. Glycine was first discovered in 1820 from gelatin hydrolysis and named for its sweet taste, derived from the Greek word γλυκύς (glykys), meaning "sweet"
. In summary, glycine is a fundamental amino acid with diverse biological functions, from protein synthesis and neurotransmission to antioxidant production and detoxification.
