Glutamine (abbreviated as Gln or Q) is one of the 20 amino acids encoded by the standard genetic code. Its side chain is an amide formed by replacing the side-chain hydroxyl of glutamic acid with an amine functional group. It can therefore be considered the amide of glutamic acid. Its codons are CAA and CAG. In human blood glutamine is the most abundant free amino acid with a concentration of about 500-900 µmol/l.. Betain structure Functions Glutamine has a variety of biochemical funct… (More on Glutamine)