Glycine
From Citizendium

Glycine is the smallest of the twenty common amino acids used by living organisms to build proteins. The side chain, or residual group of glycine is a hydrogen atom. It is one of the non-polar amino acids.
Glycine is the smallest of the twenty common amino acids used by living organisms to build proteins. The side chain, or residual group of glycine is a hydrogen atom. It is one of the non-polar amino acids.