CHEMISTRY GLOSSARY

glycine    →   glicin

Glycine is the smallest amino acid and is unique because it lacks a side chain. This gives it more conformational freedom than any other amino acid. Glycine is often found in turns and loops where other amino acids would be sterically unacceptable. Although it is formally nonpolar, it’s very small side chain makes no real contribution to hydrophobic interactions. Glycine is not essential to the human diet, as it is biosynthesized in the body from the amino acid serine.

• Abbreviations: Gly, G
• IUPAC name: 2-aminoacetic acid
• Molecular formula: C₂H₅NO₂
• Molecular weight: 75.07 g/mol

serine    →   serin

Serine is neutral amino acids with polar side chains. It is one of two hydroxyl amino acids. Both are commonly considered to by hydrophilic due to the hydrogen bonding capacity of the hydroxyl group. Serine often serves as a nucleophile in many enzyme active sites, and is best known for its role in the serine proteases. Serine is a site of phosphorylation and glycosylation which is important for enzyme regulation and cell signaling. It is not essential to the human diet, since it is synthesized in the body from other metabolites, including glycine.

• Abbreviations: Ser, S
• IUPAC name: 2-amino-3-hydroxypropanoic acid
• Molecular formula: C₃H₇NO₃
• Molecular weight: 105.09 g/mol

Dipeptide    →   Dipeptid

Dipeptide is an organic compound formed when two amino acids are joined by a peptide bond. Depending on which groups of amino acids are involved in the peptide bond four dipeptides can be formed from two different amino acids. For example, glycine (Gly) and alanine (Ala) can give two symmetrical dipeptides (GlyGly and AlaAla) and two unsymmetrical dipeptides (GlyAla and AlaGly). The naming is done by reading the sequence from the N-terminus to the C-terminus.