Glycine (abbreviated Gly), also known as glycine, is a non-essential amino acid with a chemical formula of C2H5NO2. Glycine is a constituent amino acid of the endogenous antioxidant reduced glutathione, and the body is often supplemented with exogenous sources when severe stress occurs. It is also sometimes called a semi-essential amino acid. Glycine is the simplest amino acid.
In some proteins (such as cytochrome, myoglobin, and hemoglobin) it has changed relatively little with evolution, because if a larger amino acid replaces it, the structure of the entire protein will change, so in proteins Glycine is generally In a fixed position, it will not be replaced by other amino acids.
Most proteins contain only small amounts of glycine, with collagen being an important exception, which is one-third glycine.
