Glutamine: A non-essential amino acid present abundantly throughout the body and is involved in many metabolic processes. It is synthesized from GLUTAMIC ACID and AMMONIA. It is the principal carrier of NITROGEN in the body and is an important energy source for many cells.Glutamate-Ammonia Ligase: An enzyme that catalyzes the conversion of ATP, L-glutamate, and NH3 to ADP, orthophosphate, and L-glutamine. It also acts more slowly on 4-methylene-L-glutamate. (From Enzyme Nomenclature, 1992) EC 6.3.1.2.GlutaminaseAmmonia: A colorless alkaline gas. It is formed in the body during decomposition of organic materials during a large number of metabolically important reactions. Note that the aqueous form of ammonia is referred to as AMMONIUM HYDROXIDE.Methionine SulfoximineDiazooxonorleucine: An amino acid that inhibits phosphate-activated glutaminase and interferes with glutamine metabolism. It is an antineoplastic antibiotic produced by an unidentified species of Streptomyces from Peruvian soil. (From Merck Index, 11th ed)Glutamates: Derivatives of GLUTAMIC ACID. Included under this heading are a broad variety of acid forms, salts, esters, and amides that contain the 2-aminopentanedioic acid structure.Glutamic Acid: A non-essential amino acid naturally occurring in the L-form. Glutamic acid is the most common excitatory neurotransmitter in the CENTRAL NERVOUS SYSTEM.Amino Acids: Organic compounds that generally contain an amino (-NH2) and a carboxyl (-COOH) group. Twenty alpha-amino acids are the subunits which are polymerized to form proteins.Nitrogen: An element with the atomic symbol N, atomic number 7, and atomic weight [14.00643; 14.00728]. Nitrogen exists as a diatomic gas and makes up about 78% of the earth's atmosphere by volume. It is a constituent of proteins and nucleic acids and found in all living cells.Glutamate Synthase: An enzyme that catalyzes the formation of 2 molecules of glutamate from glutamine plus alpha-ketoglutarate in the presence of NADPH. EC 1.4.1.13.Nitrogen Isotopes: Stable nitrogen atoms that have the same atomic number as the element nitrogen, but differ in atomic weight. N-15 is a stable nitrogen isotope.Ketoglutaric Acids: A family of compounds containing an oxo group with the general structure of 1,5-pentanedioic acid. (From Lehninger, Principles of Biochemistry, 1982, p442)Glutamate Dehydrogenase: An enzyme that catalyzes the conversion of L-glutamate and water to 2-oxoglutarate and NH3 in the presence of NAD+. (From Enzyme Nomenclature, 1992) EC 1.4.1.2.Amidophosphoribosyltransferase: An enzyme, involved in the early steps of purine nucleotide biosynthesis, that catalyzes the formation of 5-phosphoribosylamine from glutamine and phosphoribosylpyrophosphate. EC 2.4.2.14.Alanine: A non-essential amino acid that occurs in high levels in its free state in plasma. It is produced from pyruvate by transamination. It is involved in sugar and acid metabolism, increases IMMUNITY, and provides energy for muscle tissue, BRAIN, and the CENTRAL NERVOUS SYSTEM.Nitrogenous Group Transferases: Enzymes that catalyze the transfer of nitrogenous groups, primarily amino groups, from a donor, generally an amino acid, to an acceptor, usually a 2-oxoacid. EC 2.6.Aspartic Acid: One of the non-essential amino acids commonly occurring in the L-form. It is found in animals and plants, especially in sugar cane and sugar beets. It may be a neurotransmitter.Kinetics: The rate dynamics in chemical or physical systems.Molecular Sequence Data: Descriptions of specific amino acid, carbohydrate, or nucleotide sequences which have appeared in the published literature and/or are deposited in and maintained by databanks such as GENBANK, European Molecular Biology Laboratory (EMBL), National Biomedical Research Foundation (NBRF), or other sequence repositories.Glutamine-Fructose-6-Phosphate Transaminase (Isomerizing): An enzyme that catalyzes the synthesis of fructose-6-phosphate plus GLUTAMINE from GLUTAMATE plus glucosamine-6-phosphate.Amino Acid Sequence: The order of amino acids as they occur in a polypeptide chain. This is referred to as the primary structure of proteins. It is of fundamental importance in determining PROTEIN CONFORMATION.Transaminases: A subclass of enzymes of the transferase class that catalyze the transfer of an amino group from a donor (generally an amino acid) to an acceptor (generally a 2-keto acid). Most of these enzymes are pyridoxyl phosphate proteins. (Dorland, 28th ed) EC 2.6.1.Asparagine: A non-essential amino acid that is involved in the metabolic control of cell functions in nerve and brain tissue. It is biosynthesized from ASPARTIC ACID and AMMONIA by asparagine synthetase. (From Concise Encyclopedia Biochemistry and Molecular Biology, 3rd ed)Amino Acid Transport Systems, Neutral: Amino acid transporter systems capable of transporting neutral amino acids (AMINO ACIDS, NEUTRAL).Quaternary Ammonium Compounds: Derivatives of ammonium compounds, NH4+ Y-, in which all four of the hydrogens bonded to nitrogen have been replaced with hydrocarbyl groups. These are distinguished from IMINES which are RN=CR2.RNA, Transfer, Gln: A transfer RNA which is specific for carrying glutamine to sites on the ribosomes in preparation for protein synthesis.Glucose: A primary source of energy for living organisms. It is naturally occurring and is found in fruits and other parts of plants in its free state. It is used therapeutically in fluid and nutrient replacement.Escherichia coli: A species of gram-negative, facultatively anaerobic, rod-shaped bacteria (GRAM-NEGATIVE FACULTATIVELY ANAEROBIC RODS) commonly found in the lower part of the intestine of warm-blooded animals. It is usually nonpathogenic, but some strains are known to produce DIARRHEA and pyogenic infections. Pathogenic strains (virotypes) are classified by their specific pathogenic mechanisms such as toxins (ENTEROTOXIGENIC ESCHERICHIA COLI), etc.Azaserine: Antibiotic substance produced by various Streptomyces species. It is an inhibitor of enzymatic activities that involve glutamine and is used as an antineoplastic and immunosuppressive agent.Citric Acid Cycle: A series of oxidative reactions in the breakdown of acetyl units derived from GLUCOSE; FATTY ACIDS; or AMINO ACIDS by means of tricarboxylic acid intermediates. The end products are CARBON DIOXIDE, water, and energy in the form of phosphate bonds.Anthranilate Synthase: An enzyme that catalyzes the formation of anthranilate (o-aminobenzoate) and pyruvic acid from chorismate and glutamine. Anthranilate is the biosynthetic precursor of tryptophan and numerous secondary metabolites, including inducible plant defense compounds. EC 4.1.3.27.Hyperammonemia: Elevated level of AMMONIA in the blood. It is a sign of defective CATABOLISM of AMINO ACIDS or ammonia to UREA.Amino Acid Transport System ASC: A ubiquitous sodium-dependent neutral amino acid transporter. The preferred substrates for this transporter system include ALANINE; SERINE; and CYSTEINE.Urea: A compound formed in the liver from ammonia produced by the deamination of amino acids. It is the principal end product of protein catabolism and constitutes about one half of the total urinary solids.Mutation: Any detectable and heritable change in the genetic material that causes a change in the GENOTYPE and which is transmitted to daughter cells and to succeeding generations.Ammonium Chloride: An acidifying agent that has expectorant and diuretic effects. Also used in etching and batteries and as a flux in electroplating.Ornithine: An amino acid produced in the urea cycle by the splitting off of urea from arginine.Arginine: An essential amino acid that is physiologically active in the L-form.Leucine: An essential branched-chain amino acid important for hemoglobin formation.Carbon-Nitrogen Ligases: Enzymes that catalyze the joining of two molecules by the formation of a carbon-nitrogen bond. EC 6.3.Parenteral Nutrition, Total: The delivery of nutrients for assimilation and utilization by a patient whose sole source of nutrients is via solutions administered intravenously, subcutaneously, or by some other non-alimentary route. The basic components of TPN solutions are protein hydrolysates or free amino acid mixtures, monosaccharides, and electrolytes. Components are selected for their ability to reverse catabolism, promote anabolism, and build structural proteins.Enteral Nutrition: Nutritional support given via the alimentary canal or any route connected to the gastrointestinal system (i.e., the enteral route). This includes oral feeding, sip feeding, and tube feeding using nasogastric, gastrostomy, and jejunostomy tubes.Magnetic Resonance Spectroscopy: Spectroscopic method of measuring the magnetic moment of elementary particles such as atomic nuclei, protons or electrons. It is employed in clinical applications such as NMR Tomography (MAGNETIC RESONANCE IMAGING).Carbon Isotopes: Stable carbon atoms that have the same atomic number as the element carbon, but differ in atomic weight. C-13 is a stable carbon isotope.Liver: A large lobed glandular organ in the abdomen of vertebrates that is responsible for detoxification, metabolism, synthesis and storage of various substances.Base Sequence: The sequence of PURINES and PYRIMIDINES in nucleic acids and polynucleotides. It is also called nucleotide sequence.Biological Transport: The movement of materials (including biochemical substances and drugs) through a biological system at the cellular level. The transport can be across cell membranes and epithelial layers. It also can occur within intracellular compartments and extracellular compartments.Histidine Ammonia-Lyase: An enzyme that catalyzes the first step of histidine catabolism, forming UROCANIC ACID and AMMONIA from HISTIDINE. Deficiency of this enzyme is associated with elevated levels of serum histidine and is called histidinemia (AMINO ACID METABOLISM, INBORN ERRORS).Citrullinebeta-Alanine: An amino acid formed in vivo by the degradation of dihydrouracil and carnosine. Since neuronal uptake and neuronal receptor sensitivity to beta-alanine have been demonstrated, the compound may be a false transmitter replacing GAMMA-AMINOBUTYRIC ACID. A rare genetic disorder, hyper-beta-alaninemia, has been reported.Amino Acid Transport System A: A sodium-dependent neutral amino acid transporter that accounts for most of the sodium-dependent neutral amino acid uptake by mammalian cells. The preferred substrates for this transporter system include ALANINE; SERINE; and GLUTAMINE.Transglutaminases: Transglutaminases catalyze cross-linking of proteins at a GLUTAMINE in one chain with LYSINE in another chain. They include keratinocyte transglutaminase (TGM1 or TGK), tissue transglutaminase (TGM2 or TGC), plasma transglutaminase involved with coagulation (FACTOR XIII and FACTOR XIIIa), hair follicle transglutaminase, and prostate transglutaminase. Although structures differ, they share an active site (YGQCW) and strict CALCIUM dependence.Mutagenesis, Site-Directed: Genetically engineered MUTAGENESIS at a specific site in the DNA molecule that introduces a base substitution, or an insertion or deletion.Parenteral Nutrition: The administering of nutrients for assimilation and utilization by a patient who cannot maintain adequate nutrition by enteral feeding alone. Nutrients are administered by a route other than the alimentary canal (e.g., intravenously, subcutaneously).Aminooxyacetic Acid: A compound that inhibits aminobutyrate aminotransferase activity in vivo, thereby raising the level of gamma-aminobutyric acid in tissues.PII Nitrogen Regulatory Proteins: A family of signal transducing adaptor proteins that control the METABOLISM of NITROGEN. They are primarily found in prokaryotes.Carbamoyl-Phosphate Synthase (Glutamine-Hydrolyzing): An enzyme that catalyzes the formation of carbamoyl phosphate from ATP, carbon dioxide, and glutamine. This enzyme is important in the de novo biosynthesis of pyrimidines. EC 6.3.5.5.