serineglycine

Serineglycine, commonly written as serine-glycine or SG, is a dipeptide composed of the amino acids serine and glycine linked by a single peptide bond. In this dipeptide, the alpha amino group of glycine is connected to the alpha carboxyl group of serine. The serine residue contributes a hydroxyl-bearing side chain, while glycine provides minimal steric bulk, giving SG relatively high flexibility for a dipeptide.

Dipeptides are the simplest peptides and can occur as fragments of longer polypeptides after proteolytic cleavage, or they can be prepared synthetically for research and analytical purposes. The properties of SG reflect the characteristics of its constituent amino acids: the polarity and hydrogen-bonding potential arising from the serine hydroxyl group and the compact, flexible nature of glycine. In biological contexts, serine residues are notable for their potential involvement in phosphorylation and catalytic processes; in the SG dipeptide, these features are present within the confines of two linked amino acids.

Applications of serine-glycine include use as a model dipeptide in studies of protease specificity, peptide synthesis, and analytical techniques such as chromatography and mass spectrometry, where defined dipeptides serve as standards. While SG is one of many possible dipeptides, it provides a straightforward example of dipeptide structure and function in biochemical research and education.