Glutamine was first discovered by Schulze in 1883, who managed to isolate it from the beet juice. Later on, it turned out that glutamine can also be found in abundance in a wheat gliadin. Finally, in 1935, the synthesis of glutamine from ammonium and glutamate was explained and described by Krebs, who used the guinea pig and the rat kidney in his research.

Chemical Structure
Structure of Glutamine

IUPAC Name: (2S)-2,5-Diamino-5-oxopentanoic acid
Symbol: Three-letter code - Gln. One-letter code - Q
Molecular Weight (Molar Mass): 146.1445 g/mol
Molecular Formula (Structural Formula): C5H10N2O3
Canonical SMILES: C(CC(=O)N)C(C(=O)O)N
Isomeric SMILES: C(CC(=O)N)[C@@H](C(=O)O)N
CAS Number: 56-85-9
MDL Number: MFCD00008044
Melting point: 185 °C
Solubility in water: 35 g/L (20 °C); pKa - 2,17; pKb - 9,13
2D Molfile: Get the molfile
3D PDB file: Get the PDB file
Other names: L-Glutamic acid 5-amide; 2-Aminoglutaramic acid; L-2-Aminoglutaramidic acid; Glutamic acid amide; Glutamic acid 5-amide; gamma-Glutamine; Levoglutamid; Levoglutamide

Glutamine, also known as L-Glutamine, seems to be the most active amino acid involved in lots of metabolic processes. For example, glutamine is converted to glucose if your body needs more glucose as an energy source. Besides, it also participates in maintaining of a normal blood glucose level and the proper pH range. In fact, glutamine was recognized as the most abundant free amino acid found in the human muscles and in plasma. A human body utilizes this amino acid at high rates for rapidly dividing cells, like leucocytes, in order to supply them with an energy, i.e., to create the best conditions for the nucleotide biosynthesis. In other words, glutamine is considered to be vital for the proper immune function.

The major part of glutamine is stored in the muscles and in the lungs, where it is mostly produced. Glutamine is recognized as a very important amino acid helping removing excess ammonia, which is a usual waste product in the human body. This amino acid also turned out to be important for the digestion and for the normal brain function. Glutamine aids to protect the lining of the gastrointestinal tract and helps athletes to keep fit.

The scientists have agreed that glutamine is the most abundant amino acid or the building block of a protein in the human body. But where can you get it from? Normally, your body can produce enough amino acid for its regular needs, but sometimes an extreme stress like a very intensive exercise or an illness may cause a shortage of glutamine because your body will need more amino acid than it can produce. People naturally are able to get enough glutamine without taking a supplement as the human body produces it. Besides, you can also get more glutamine in your diet. Meanwhile, some medical conditions like injuries, surgery, and stress usually lower the levels of this amino acid. As a matter of fact, when your body is stressed under such conditions, it releases the hormone called cortisol into your bloodstream. It's high levels of this hormone that lower the human body's stores of glutamine, implying that you may need to take a glutamine supplement to help your body to restore.