PolyaminesBiogenic Polyamines: Biogenic amines having more than one amine group. These are long-chain aliphatic compounds that contain multiple amino and/or imino groups. Because of the linear arrangement of positive charge on these molecules, polyamines bind electrostatically to ribosomes, DNA, and RNA.Spermidine: A polyamine formed from putrescine. It is found in almost all tissues in association with nucleic acids. It is found as a cation at all pH values, and is thought to help stabilize some membranes and nucleic acid structures. It is a precursor of spermine.Spermine: A biogenic polyamine formed from spermidine. It is found in a wide variety of organisms and tissues and is an essential growth factor in some bacteria. It is found as a polycation at all pH values. Spermine is associated with nucleic acids, particularly in viruses, and is thought to stabilize the helical structure.Putrescine: A toxic diamine formed by putrefaction from the decarboxylation of arginine and ornithine.Ornithine Decarboxylase: A pyridoxal-phosphate protein, believed to be the rate-limiting compound in the biosynthesis of polyamines. It catalyzes the decarboxylation of ornithine to form putrescine, which is then linked to a propylamine moiety of decarboxylated S-adenosylmethionine to form spermidine.Eflornithine: An inhibitor of ORNITHINE DECARBOXYLASE, the rate limiting enzyme of the polyamine biosynthetic pathway.Cadaverine: A foul-smelling diamine formed by bacterial decarboxylation of lysine.Adenosylmethionine Decarboxylase: An enzyme that catalyzes the decarboxylation of S-adenosyl-L-methionine to yield 5'-deoxy-(5'-),3-aminopropyl-(1), methylsulfonium salt. It is one of the enzymes responsible for the synthesis of spermidine from putrescine. EC Organic chemicals which have two amino groups in an aliphatic chain.Ornithine: An amino acid produced in the urea cycle by the splitting off of urea from arginine.Spermidine Synthase: An enzyme that catalyzes the transfer of the propylamine moiety from 5'-deoxy-5'-S-(3-methylthiopropylamine)sulfonium adenosine to putrescine in the biosynthesis of spermidine. The enzyme has a molecular weight of approximately 73,000 kDa and is composed of two subunits of equal size.Carboxy-Lyases: Enzymes that catalyze the addition of a carboxyl group to a compound (carboxylases) or the removal of a carboxyl group from a compound (decarboxylases). EC 4.1.1.Oxidoreductases Acting on CH-NH Group Donors: Enzymes catalyzing the dehydrogenation of secondary amines, introducing a C=N double bond as the primary reaction. In some cases this is later hydrolyzed.Acetyltransferases: Enzymes catalyzing the transfer of an acetyl group, usually from acetyl coenzyme A, to another compound. EC 2.3.1.Agmatine: Decarboxylated arginine, isolated from several plant and animal sources, e.g., pollen, ergot, herring sperm, octopus muscle.Amines: A group of compounds derived from ammonia by substituting organic radicals for the hydrogens. (From Grant & Hackh's Chemical Dictionary, 5th ed)Amine Oxidase (Copper-Containing): A group of enzymes including those oxidizing primary monoamines, diamines, and histamine. They are copper proteins, and, as their action depends on a carbonyl group, they are sensitive to inhibition by semicarbazide.Arginase: A ureahydrolase that catalyzes the hydrolysis of arginine or canavanine to yield L-ornithine (ORNITHINE) and urea. Deficiency of this enzyme causes HYPERARGININEMIA. EC The rate dynamics in chemical or physical systems.Cyclohexylamines: A family of alicyclic hydrocarbons containing an amine group with the general formula R-C6H10NH2.Magnesium: A metallic element that has the atomic symbol Mg, atomic number 12, and atomic weight 24.31. It is important for the activity of many enzymes, especially those involved in OXIDATIVE PHOSPHORYLATION.Arginine: An essential amino acid that is physiologically active in the L-form.UreohydrolasesPyrodictiaceae: A family of archaea, in the order DESULFUROCOCCALES consisting of anaerobic coccoid to disc-shaped cells. They grow either chemolithoautotrophically or by FERMENTATION. Three genera are recognized: Pyrodictium, Hyperthermus, and Pyrolobus.