Glutamine
Glutamine is a protein-building amino acid that transports nitrogen between tissues and fuels cells, especially in the intestine and immune system.
Glutaminolysis: The metabolic breakdown of glutamine into glutamate and downstream products, including α-ketoglutarate. This pathway releases glutamine’s carbon skeleton for energy production and biosynthesis.
Small intestine: The digestive tract segment where most nutrient absorption occurs. Intestinal cells use glutamine as a major fuel and metabolic substrate.
Amino acid: An organic molecule containing amino and carboxyl groups; amino acids are protein building blocks and metabolic intermediates. Glutamine is one member of this broad chemical and biological family.
Urea cycle: A liver pathway that converts toxic ammonia into urea for excretion. Nitrogen delivered in glutamine can ultimately enter this principal route of nitrogen disposal.
Glutaminase: An enzyme that converts glutamine into glutamate and ammonia. It initiates glutamine breakdown in tissues that consume or process the amino acid.
Enterocyte: An epithelial cell lining the small intestine that absorbs nutrients and helps maintain the gut barrier. Enterocytes consume glutamine to support energy needs and intestinal function.
Protein: A biological molecule made of one or more chains of amino acids folded into functional structures. Glutamine can be incorporated into proteins as one of their constituent amino acids.
Kidney: An organ that filters blood, balances body fluids and electrolytes, and excretes waste. Renal glutamine metabolism produces ammonium and helps regulate acid–base balance.
Glutamine synthetase: An enzyme that combines glutamate and ammonia to synthesize glutamine using ATP. It captures ammonia in glutamine, enabling safer nitrogen transport between tissues.
Lymphocyte: A white blood cell, including B cells, T cells, and natural killer cells, involved in adaptive or innate immunity. Activated lymphocytes use glutamine to support growth, energy, and nucleotide synthesis.