Complement C5a: The minor fragment formed when C5 convertase cleaves C5 into C5a and COMPLEMENT C5B. C5a is a 74-amino-acid glycopeptide with a carboxy-terminal ARGININE that is crucial for its spasmogenic activity. Of all the complement-derived anaphylatoxins, C5a is the most potent in mediating immediate hypersensitivity (HYPERSENSITIVITY, IMMEDIATE), smooth MUSCLE CONTRACTION; HISTAMINE RELEASE; and migration of LEUKOCYTES to site of INFLAMMATION.Aspartate Aminotransferases: Enzymes of the transferase class that catalyze the conversion of L-aspartate and 2-ketoglutarate to oxaloacetate and L-glutamate. EC Carbamoyltransferase: An enzyme that catalyzes the conversion of carbamoyl phosphate and L-aspartate to yield orthophosphate and N-carbamoyl-L-aspartate. (From Enzyme Nomenclature, 1992) EC 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.Aspartate Kinase: An enzyme that catalyzes the formation of beta-aspartyl phosphate from aspartic acid and ATP. Threonine serves as an allosteric regulator of this enzyme to control the biosynthetic pathway from aspartic acid to threonine. EC Transaminase: An enzyme that catalyzes the conversion of L-alanine and 2-oxoglutarate to pyruvate and L-glutamate. (From Enzyme Nomenclature, 1992) EC Ammonia-Lyase: An enzyme that catalyzes the conversion of aspartic acid to ammonia and fumaric acid in plants and some microorganisms. EC Methyl Ester: A non-selective inhibitor of nitric oxide synthase. It has been used experimentally to induce hypertension.Receptors, Amino Acid: Cell surface proteins that bind amino acids and trigger changes which influence the behavior of cells. Glutamate receptors are the most common receptors for fast excitatory synaptic transmission in the vertebrate central nervous system, and GAMMA-AMINOBUTYRIC ACID and glycine receptors are the most common receptors for fast inhibition.Methyl Parathion: The methyl homolog of parathion. An effective, but highly toxic, organothiophosphate insecticide and cholinesterase inhibitor.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.Aspartate Aminotransferase, Mitochondrial: An aspartate aminotransferase found in MITOCHONDRIA.Kinetics: The rate dynamics in chemical or physical systems.Phosphonoacetic Acid: A simple organophosphorus compound that inhibits DNA polymerase, especially in viruses and is used as an antiviral agent.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.Carbamyl Phosphate: The monoanhydride of carbamic acid with PHOSPHORIC ACID. It is an important intermediate metabolite and is synthesized enzymatically by CARBAMYL-PHOSPHATE SYNTHASE (AMMONIA) and CARBAMOYL-PHOSPHATE SYNTHASE (GLUTAMINE-HYDROLYZING).Methyl Methanesulfonate: An alkylating agent in cancer therapy that may also act as a mutagen by interfering with and causing damage to DNA.Dihydroorotase: An enzyme that, in the course of pyrimidine biosynthesis, catalyzes ring closure by removal of water from N-carbamoylaspartate to yield dihydro-orotic acid. EC 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.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.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.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.Cytidine Triphosphate: Cytidine 5'-(tetrahydrogen triphosphate). A cytosine nucleotide containing three phosphate groups esterified to the sugar moiety.Methyl Chloride: A hydrocarbon used as an industrial solvent. It has been used as an aerosal propellent, as a refrigerant and as a local anesthetic. (From Martindale, The Extra Pharmacopoeia, 31st ed, p1403)Pyridoxal Phosphate: This is the active form of VITAMIN B 6 serving as a coenzyme for synthesis of amino acids, neurotransmitters (serotonin, norepinephrine), sphingolipids, aminolevulinic acid. During transamination of amino acids, pyridoxal phosphate is transiently converted into pyridoxamine phosphate (PYRIDOXAMINE).Liver: A large lobed glandular organ in the abdomen of vertebrates that is responsible for detoxification, metabolism, synthesis and storage of various substances.Homoserine Dehydrogenase: An enzyme that catalyzes the reduction of aspartic beta-semialdehyde to homoserine, which is the branch point in biosynthesis of methionine, lysine, threonine and leucine from aspartic acid. EC 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.Aminooxyacetic Acid: A compound that inhibits aminobutyrate aminotransferase activity in vivo, thereby raising the level of gamma-aminobutyric acid in tissues.Binding Sites: The parts of a macromolecule that directly participate in its specific combination with another molecule.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.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).Succinates: Derivatives of SUCCINIC ACID. Included under this heading are a broad variety of acid forms, salts, esters, and amides that contain a 1,4-carboxy terminated aliphatic structure.Methylation: Addition of methyl groups. In histo-chemistry methylation is used to esterify carboxyl groups and remove sulfate groups by treating tissue sections with hot methanol in the presence of hydrochloric acid. (From Stedman, 25th ed)Aspartate-Semialdehyde Dehydrogenase: An enzyme that catalyzes the conversion of L-aspartate 4-semialdehyde, orthophosphate, and NADP+ to yield L-4-aspartyl phosphate and NADPH. EC, Molecular: Models used experimentally or theoretically to study molecular shape, electronic properties, or interactions; includes analogous molecules, computer-generated graphics, and mechanical structures.Mutagenesis, Site-Directed: Genetically engineered MUTAGENESIS at a specific site in the DNA molecule that introduces a base substitution, or an insertion or deletion.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 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.Pyridoxamine: The 4-aminomethyl form of VITAMIN B 6. During transamination of amino acids, PYRIDOXAL PHOSPHATE is transiently converted into pyridoxamine phosphate.Protein Conformation: The characteristic 3-dimensional shape of a protein, including the secondary, supersecondary (motifs), tertiary (domains) and quaternary structure of the peptide chain. PROTEIN STRUCTURE, QUATERNARY describes the conformation assumed by multimeric proteins (aggregates of more than one polypeptide chain).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)Oxaloacetates: Derivatives of OXALOACETIC ACID. Included under this heading are a broad variety of acid forms, salts, esters, and amides that include a 2-keto-1,4-carboxy aliphatic structure.MalatesStructure-Activity Relationship: The relationship between the chemical structure of a compound and its biological or pharmacological activity. Compounds are often classed together because they have structural characteristics in common including shape, size, stereochemical arrangement, and distribution of functional groups.Catalysis: The facilitation of a chemical reaction by material (catalyst) that is not consumed by the reaction.Glycine: A non-essential amino acid. It is found primarily in gelatin and silk fibroin and used therapeutically as a nutrient. It is also a fast inhibitory neurotransmitter.Glycine Plasma Membrane Transport Proteins: A family of sodium chloride-dependent neurotransmitter symporters that transport the amino acid GLYCINE. They differ from GLYCINE RECEPTORS, which signal cellular responses to GLYCINE. They are located primarily on the PLASMA MEMBRANE of NEURONS; GLIAL CELLS; EPITHELIAL CELLS; and RED BLOOD CELLS where they remove inhibitory neurotransmitter glycine from the EXTRACELLULAR SPACE.Receptors, N-Methyl-D-Aspartate: A class of ionotropic glutamate receptors characterized by affinity for N-methyl-D-aspartate. NMDA receptors have an allosteric binding site for glycine which must be occupied for the channel to open efficiently and a site within the channel itself to which magnesium ions bind in a voltage-dependent manner. The positive voltage dependence of channel conductance and the high permeability of the conducting channel to calcium ions (as well as to monovalent cations) are important in excitotoxicity and neuronal plasticity.Sarcosine: An amino acid intermediate in the metabolism of choline.Amino Acid Transport Systems, Neutral: Amino acid transporter systems capable of transporting neutral amino acids (AMINO ACIDS, NEUTRAL).N-Methylaspartate: An amino acid that, as the D-isomer, is the defining agonist for the NMDA receptor subtype of glutamate receptors (RECEPTORS, NMDA).Kynurenic Acid: A broad-spectrum excitatory amino acid antagonist used as a research tool.