Difference Between Glutamine and L-Glutamine

Glutamine vs L-Glutamine

Amino acid is a simple molecule formed with C, H, O, N and may be S. It has the following general structure.

There are about 20 common amino acids. All the amino acids have a –COOH, -NH₂ groups and a –H bonded to a carbon. The carbon is a chiral carbon, and alpha amino acids are the most important in the biological world. D-amino acids are not found in proteins and not a part of metabolism of higher organisms. However, several are important in the structure and metabolism of lower forms of life. In addition to common amino acids, there are a number of non-protein derived amino acids, many of which are either metabolic intermediates or parts of non-protein biomolecules (ornithine, citrulline). The R group differs from amino acid, to amino acid. The simplest amino acid with R group being H is glycine. According to the R group, amino acids can be categorized into aliphatic, aromatic, non polar, polar, positively charged, negatively charged, or polar uncharged, etc. Amino acids present as zwitter ions in the physiological pH 7.4. Amino acids are the building blocks of proteins. When two amino acids join together to form a dipeptide, the combination takes place in the -NH₂ group of one amino acid with –COOH group of another amino acid. A water molecule is removed, and the formed bond is known as a peptide bond.

Glutamine

Glutamine is one of the main amino acids which is not essential. It is abbreviated as Gln. Its R group has an additional amine group. It is related to the structure of glutamic acid except, glutamine has an amide side chain instead of the hydroxyl group of glutamic acid. Glutamine has the following structure.

Glutamine is the most abundant free amino acid in human blood. Its concentration in blood is about 500-900 µmol/L. Glutamine is produced by the CAA and CAG codons. It is synthesized from glutamate and ammonia by the glutamate synthetase enzyme. It is mainly produced in muscles, and small amounts are released from lung and brain.

Glutamine has various functions in the biological systems. It participates in forming proteins as any other amino acid would do. Glutamine is responsible for regulating the acid base balance in the kidneys. It functions as a nitrogen and carbon source as well as an energy source after glucose. The ammonia produced from the metabolic activities is toxic to cells when it is free. Glutamine is a nontoxic way of transporting ammonia in the blood.

L-Glutamine

Glutamine is a chiral molecule which has non-superimposable mirror images. Therefore, there are two isomers to glutamine as L-glutamine and d-glutamine. Among both, L-glutamine is abundant in the body and participates in various functions.

Beef, chicken, eggs, fish, milk, cabbage, beets, beans, spinach and parsley are dietary sources of L-glutamine.

Glutamine vs L-Glutamine