Glutamine is one of the 20 protein amino acids, whose three-letter symbol is Gln and one-letter symbol is Q. Its side chain has a terminal amide group (-CONH2). The chemical formula for glutamine is C5H10N2O3, which gives a molecular weight of 146.14. It has an isoelectric point (pI) of 5.65. It is easily hydrolyzed to give the amino acid glutamic acid (Glu) and ammonia. Both glutamic acid and glutamine are determined as glutamic acid in the hydrolysate of proteins. After acid hydrolysis, it is thus unknown whether the original species was Glu or Gln, and thus it is reported as Glx.