Glutamine Metabolism

Definition

Glutamine is the most abundant free amino acid in the human body. A large number of tissues and cells of the body utilize glutamine at high rates, and availability of glutamine is essential for their function. It plays a central role in several important functions of the human cell. These functions include:

• Essential metabolic precursor in nucleotide and glucose biosynthesis

• Constituent for proteins – usually 5–10% of the total amino acid content

• Energy substrate for immunocompetent cells and enterocytes

• Precursor for the important excitatory neurotransmitter glutamate in the brain

• A pathway for glutamate transport out of the brain

• Precursor for the antioxidant glutathione

• Interorgan transporter of nitrogen

• A substrate for renal ammoniagenesis and acid-base regulation

• Direct effects on gene expression

Characteristics

Biochemistry

Glutamine has a molecular weight of 146 Da and is built up from an alfa-ketoglutarate carbon skeleton and two amino groups as illustrated in Fig. 1...