Isoglutamine or α-glutamine is a gamma

amino acid Amino acids are organic compounds that contain both amino and carboxylic acid functional groups. Although hundreds of amino acids exist in nature, by far the most important are the alpha-amino acids, which comprise proteins. Only 22 alpha a ...

derived from glutamic acid by substituting the

carboxyl group In organic chemistry, a carboxylic acid is an organic acid that contains a carboxyl group () attached to an R-group. The general formula of a carboxylic acid is or , with R referring to the alkyl, alkenyl, aryl, or other group. Carboxylic ...

in position 1 with an

amide In organic chemistry, an amide, also known as an organic amide or a carboxamide, is a compound with the general formula , where R, R', and R″ represent organic groups or hydrogen atoms. The amide group is called a peptide bond when it i ...

group. This is in contrast to the

proteinogenic Proteinogenic amino acids are amino acids that are incorporated biosynthetically into proteins during translation. The word "proteinogenic" means "protein creating". Throughout known life, there are 22 genetically encoded (proteinogenic) amino aci ...

amino acid

glutamine Glutamine (symbol Gln or Q) is an α-amino acid that is used in the biosynthesis of proteins. Its side chain is similar to that of glutamic acid, except the carboxylic acid group is replaced by an amide. It is classified as a charge-neutral ...

, which is the 5-amide of glutamic acid. Isoglutamine can form the C-terminus of a peptide chain, as in

muramyl dipeptide Muramyl dipeptide is constituent of both Gram-positive and Gram-negative bacteria composed of N-acetylmuramic acid linked by its lactic acid moiety to the N-terminus of an L-alanine D- isoglutamine dipeptide. It can be recognized by the immune s ...

(MDP), a constituent of

bacteria Bacteria (; singular: bacterium) are ubiquitous, mostly free-living organisms often consisting of one Cell (biology), biological cell. They constitute a large domain (biology), domain of prokaryotic microorganisms. Typically a few micrometr ...

l cell walls. It can also occur inside a peptide chain, in which case the chain is continued at the carboxyl group and isoglutamine behaves as a γ-amino acid, as in mifamurtide, a synthetic derivative of MDP used to treat

osteosarcoma An osteosarcoma (OS) or osteogenic sarcoma (OGS) (or simply bone cancer) is a cancerous tumor in a bone. Specifically, it is an aggressive malignant neoplasm that arises from primitive transformed cells of mesenchymal origin (and thus a sarcoma ...

Stereochemistry

Substituting -glutamic acid, the proteinogenic enantiomer, gives -isoglutamine, which has ''S'' configuration. -Isoglutamine, the derivative of the nonproteinogenic -glutamic acid, has ''R'' configuration. The latter is the form occurring in MDP and mifamurtide.

References

{{reflist Amino acids