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Citrulline
The organic compound citrulline is an α-amino acid. Its name is derived from ''citrullus'', the Latin word for watermelon. Although named and described by gastroenterologists since the late 19th century, it was first isolated from watermelon in 1914 by Japanese researchers Yotaro Koga and Ryo OdakeEarly references spell Ryo Odake's name as ''Ryo Othake''. and further codified by Mitsunori Wada of Tokyo Imperial University in 1930. It has the formula H2NC(O)NH(CH2)3CH(NH2)CO2H. It is a key intermediate in the urea cycle, the pathway by which mammals excrete ammonia by converting it into urea. Citrulline is also produced as a byproduct of the enzymatic production of nitric oxide from the amino acid arginine, catalyzed by nitric oxide synthase. Biosynthesis Citrulline can be derived from: * from arginine via nitric oxide synthase, as a byproduct of the production of nitric oxide for signaling purposes * from ornithine through the breakdown of proline or glutamine/glutamate * from ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Urea Cycle
The urea cycle (also known as the ornithine cycle) is a cycle of biochemical reactions that produces urea (NH2)2CO from ammonia (NH3). Animals that use this cycle, mainly amphibians and mammals, are called ureotelic. The urea cycle converts highly toxic ammonia to urea for excretion. This cycle was the first metabolic cycle to be discovered ( Hans Krebs and Kurt Henseleit, 1932), five years before the discovery of the TCA cycle. This cycle was described in more detail later on by Ratner and Cohen. The urea cycle takes place primarily in the liver and, to a lesser extent, in the kidneys. Function Amino acid catabolism results in waste ammonia. All animals need a way to excrete this product. Most aquatic organisms, or ammonotelic organisms, excrete ammonia without converting it. Organisms that cannot easily and safely remove nitrogen as ammonia convert it to a less toxic substance, such as urea, via the urea cycle, which occurs mainly in the liver. Urea produced by the liver is th ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Carbromal
Carbromal is a hypnotic/sedative originally synthesized in 1909 by Bayer and subsequently marketed as Adalin. The drug was later sold by Parke-Davis in combination with pentobarbital, under the name Carbrital. Synthesis Diethylmalonic acid [510-20-3] (1) is decarboxylated to 2-ethylvaleric acid [20225-24-5] (2). The Hell-Volhard-Zelinsky reaction converts this to 2-Bromo-2-Ethylbutyryl Bromide [26074-53-3] (3). Reaction with urea with affords carbromal (4). See also * Acecarbromal * Bromisoval * Apronal References Hypnotics Sedatives Ureas Organobromides GABAA receptor positive allosteric modulators {{sedative-stub ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Carbamoyl Phosphate
Carbamoyl phosphate is an anion of biochemical significance. In land-dwelling animals, it is an intermediary metabolite in nitrogen disposal through the urea cycle and the synthesis of pyrimidines. Its enzymatic counterpart, carbamoyl phosphate synthetase I (CPS I), interacts with a class of molecules called sirtuins, NAD dependent protein deacetylases, and ATP to form carbamoyl phosphate. CP then enters the urea cycle in which it reacts with ornithine (a process catalyzed by the enzyme ornithine transcarbamylase) to form citrulline. Production It is produced from bicarbonate, ammonia (derived from amino acids), and phosphate (from ATP). The synthesis is catalyzed by the enzyme carbamoyl phosphate synthetase. This uses three reactions as follows: * + ATP → ADP + (carboxyl phosphate) * + NH3 + OH− → + −O–C(O)NH2 + H2O *−O–C(O)NH2 + ATP → ADP + Clinical significance A defect in the CPS I enzyme, and a subsequent deficiency in the production of ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Aceglutamide
Aceglutamide (brand name Neuramina), or aceglutamide aluminum (brand name Glumal), also known as acetylglutamine, is a psychostimulant, nootropic, and antiulcer agent that is marketed in Spain and Japan. It is an acetylated form of the amino acid L-glutamine, the precursor of glutamate in the body and brain. Aceglutamide functions as a prodrug to glutamine with improved potency and stability. Aceglutamide is used as a psychostimulant and nootropic, while aceglutamide aluminum is used in the treatment of ulcers. Aceglutamide can also be used as a liquid-stable source of glutamine to prevent damage from protein energy malnutrition., abandoned during patent examination The drug has shown neuroprotective effects in an animal model of cerebral ischemia Brain ischemia is a condition in which there is insufficient bloodflow to the brain to meet metabolic demand. This leads to poor oxygen supply or cerebral hypoxia and thus leads to the death of brain tissue or cerebral infarction/isch ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
N-Acetylaspartic Acid
''N''-Acetylaspartic acid, or ''N''-acetylaspartate (NAA), is a derivative of aspartic acid with a formula of C6H9NO5 and a molecular weight of 175.139. NAA is the second-most-concentrated molecule in the brain after the amino acid glutamate. It is detected in the adult brain in neurons, oligodendrocytes and myelin and is synthesized in the mitochondria from the amino acid aspartic acid and acetyl-coenzyme A. Function The various functions served by NAA are under investigation, but the primary proposed functions include: * Neuronal osmolyte that is involved in fluid balance in the brain * Source of acetate for lipid and myelin synthesis in oligodendrocytes, the glial cells that myelinate neuronal axons * Precursor for the synthesis of the neuronal dipeptide N-Acetylaspartylglutamate * Contributor to energy production from the amino acid glutamate in neuronal mitochondria In the brain, NAA was thought to be present predominantly in neuronal cell bodies, where it acts as a ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Bromisoval
Bromisoval (INN), commonly known as bromovalerylurea, is a hypnotic and sedative of the bromoureide group discovered by Knoll in 1907 and patented in 1909. It is marketed over the counter in Asia under various trade names (such as ''Brovarin''), usually in combination with nonsteroidal anti-inflammatory drugs. Chronic use of bromisoval has been associated with bromine poisoning. Bromisoval can be prepared by bromination of isovaleric acid by the Hell-Volhard-Zelinsky reaction followed by reaction with urea. See also * Acecarbromal * Carbromal Carbromal is a hypnotic/sedative originally synthesized in 1909 by Bayer and subsequently marketed as Adalin. The drug was later sold by Parke-Davis in combination with pentobarbital, under the name Carbrital. Synthesis Diethylmalonic acid 10 ... * Apronal References Hypnotics">Apronal.html" ;"title="10 ... * Apronal">10 ... * Apronal References Hypnotics Sedatives Organobromides GABAA receptor positive allosteri ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
N-Acetylglutamic Acid
''N''-Acetylglutamic acid (also referred to as ''N''-acetylglutamate, abbreviated NAG, chemical formula C7H11NO5) is biosynthesized from glutamate and acetylornithine by ornithine acetyltransferase, and from glutamic acid and acetyl-CoA by the enzyme ''N''-acetylglutamate synthase. The reverse reaction, hydrolysis of the acetyl group, is catalyzed by a specific hydrolase. It is the first intermediate involved in the biosynthesis of arginine in prokaryotes and simple eukaryotes and a regulator in the process known as the urea cycle that converts toxic ammonia to urea for excretion from the body in vertebrates. Discovery ''N''-Acetylglutamic acid is an extracellular metabolite isolated from the prokaryote Rhizobium trifolii that was characterized using many structure determination techniques such as proton nuclear magnetic resonance (1H NMR) spectroscopy, Fourier-transform infrared spectroscopy, and gas chromatography-mass spectrometry. In ''Rhizobium'', extracellular buil ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Pivagabine
Pivagabine (INN; brand name Tonerg), also known as ''N''-pivaloyl-γ-aminobutyric acid or ''N''-pivaloyl-GABA, is an antidepressant and anxiolytic drug which was introduced in Italy in 1997 for the treatment of depressive and maladaptive syndromes. But it was discontinued in Italy (according to Martindale). Originally believed to function as a prodrug to GABA, pivagabine is now believed to act somehow via modulation of corticotropin-releasing factor (CRF). See also * Fengabine Fengabine (SL-79,229) is a drug which was investigated as an antidepressant but was never marketed. Its mechanism of action is unknown, but its antidepressant effects are reversed by GABAA receptor antagonists like bicuculline and it has hence ... References {{Anxiolytics Antidepressants Carboxamides Drugs with unknown mechanisms of action GABA analogues ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Arginine
Arginine is the amino acid with the formula (H2N)(HN)CN(H)(CH2)3CH(NH2)CO2H. The molecule features a guanidino group appended to a standard amino acid framework. At physiological pH, the carboxylic acid is deprotonated (−CO2−) and both the amino and guanidino groups are protonated, resulting in a cation. Only the -arginine (symbol Arg or R) enantiomer is found naturally. Arg residues are common components of proteins. It is encoded by the codons CGU, CGC, CGA, CGG, AGA, and AGG. The guanidine group in arginine is the precursor for the biosynthesis of nitric oxide. Like all amino acids, it is a white, water-soluble solid. History Arginine was first isolated in 1886 from yellow lupin seedlings by the German chemist Ernst Schulze and his assistant Ernst Steiger. He named it from the Greek ''árgyros'' (ἄργυρος) meaning "silver" due to the silver-white appearance of arginine nitrate crystals. In 1897, Schulze and Ernst Winterstein (1865–1949) determined the structure ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Root Sheath (hair)
The inner or epidermic coat of the hair follicle is closely adherent to the root of the hair, and consists of two strata named respectively the outer and inner root sheaths. Outer root sheath The outer root sheath corresponds with the stratum mucosum (stratum germinativum and stratum spinosum) of the epidermis, and resembles it in the rounded form and soft character of its cells; at the bottom of the hair follicle these cells become continuous with those of the root of the hair. Inner root sheath The inner root sheath (IRS) consists of # a delicate cuticle next the hair, composed of a single layer of imbricated scales with atrophied nuclei; # Huxley's layer # Henle's layer Henle's layer is the third and the outermost layer of the inner root sheath of the hair follicle, consisting of a single layer of cubical cells with clear flattened nuclei. It is named after German physician, pathologist and anatomist A ... The term "trichilemmal" refers to the outer root she ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
TCHH
Trichohyalin is a protein that in mammals is encoded by the ''TCHH'' gene. Discovery In 1903 the name ''trichohyalin'' was assigned to the granules of the inner root sheath (IRS) of hair follicles discovered by Hans Vörner. In 1986 the name was reassigned to a protein isolated from sheep wool follicles. Gene location The human TCHH is located on the long (q) arm of chromosome 1 at region 2 band 1 sub-band 3 (1q21.3), from base pair 152,105,403 to base pair 152,116,368map. This region in chromosome 1q21 is known as the epidermal differentiation complex, since it harbors over fifty other genes involved in keratinocyte differentiation. Gene coding sequence contains 5829 nucleotides. Gene orthologs were identified in most mammals including mice, chickens, rats, pigs, sheep, horses and other species. Protein localisation Trichohyalin is highly expressed in the inner root sheath cells of the hair follicle and medulla. It was also detected in the granular layer and stratum corne ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Asymmetric Dimethylarginine
Asymmetric dimethylarginine (ADMA) is a naturally occurring chemical found in blood plasma. It is a metabolic by-product of continual protein modification processes in the cytoplasm of all human cells. It is closely related to L-arginine, a conditionally essential amino acid. ADMA interferes with L-arginine in the production of nitric oxide (NO), a key chemical involved in normal endothelial function and, by extension, cardiovascular health. Discovery Patrick Vallance and his London co-workers first noted the interference role for asymmetric dimethylarginine in the early 1990s. Today biochemical and clinical research continues into the role of ADMA in cardiovascular disease, diabetes mellitus, erectile dysfunction and certain forms of kidney disease. Synthesis and regulation in the body Asymmetric dimethylarginine is created in protein methylation, a common mechanism of post-translational protein modification. This reaction is catalyzed by an enzyme set called protein arginine N- ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
