(GTP cyclohydrolase I) or GTP 7,8-8,9-dihydrolase (pyrophosphate-forming) (GTP cyclohydrolase II). An enzyme group that hydrolyzes the imidazole ring of GTP, releasing carbon-8 as formate. Two C-N bonds are hydrolyzed and the pentase unit is isomerized. This is the first step in the synthesis of folic acid from GTP. EC (GTP cyclohydrolase I) and EC (GTP cyclohydrolase II).
A natural product that has been considered as a growth factor for some insects.
An aminohydrolase that catalyzes the hydrolysis of 5,10-methenyltetrahydrofolate to 10-formyltetrahydrofolate. In most higher eucaryotic organisms this enzyme also includes METHYLENETETRAHYDROFOLATE DEHYDROGENASE (NADP) and FORMATE-TETRAHYDROFOLATE LIGASE activities.
Compounds based on 2-amino-4-hydroxypteridine.
Compounds based on pyrazino[2,3-d]pyrimidine which is a pyrimidine fused to a pyrazine, containing four NITROGEN atoms.
Enzymes that catalyze the cleavage of a phosphorus-oxygen bond by means other than hydrolysis or oxidation. EC 4.6.
Purine bases related to hypoxanthine, an intermediate product of uric acid synthesis and a breakdown product of adenine catabolism.
An attitude or posture due to the co-contraction of agonists and antagonist muscles in one region of the body. It most often affects the large axial muscles of the trunk and limb girdles. Conditions which feature persistent or recurrent episodes of dystonia as a primary manifestation of disease are referred to as DYSTONIC DISORDERS. (Adams et al., Principles of Neurology, 6th ed, p77)
An NADP-dependent oxidoreductase that catalyses the conversion of 5,10-methyleneterahydrofolate to 5,10-methenyl-tetrahydrofolate. In higher eukaryotes a trifunctional enzyme exists with additional METHENYLTETRAHYDROFOLATE CYCLOHYDROLASE and FORMATE-TETRAHYDROFOLATE LIGASE activity. The enzyme plays an important role in the synthesis of 5-methyltetrahydrofolate, the methyl donor for the VITAMIN B12-dependent remethylation of HOMOCYSTEINE to METHIONINE via METHIONINE SYNTHETASE.
Guanosine 5'-(tetrahydrogen triphosphate). A guanine nucleotide containing three phosphate groups esterified to the sugar moiety.
Catalyze the hydrolysis of nucleotides with the elimination of ammonia.
A pteridine derivative present in body fluids; elevated levels result from immune system activation, malignant disease, allograft rejection, and viral infections. (From Stedman, 26th ed) Neopterin also serves as a precursor in the biosynthesis of biopterin.
A carbon-nitrogen ligase that catalyzes the formation of 10-formyltetrahydrofolate from formate and tetrahydrofolate in the presence of ATP. In higher eukaryotes the enzyme also contains METHYLENETETRAHYDROFOLATE DEHYDROGENASE (NADP+) and METHENYLTETRAHYDROFOLATE CYCLOHYDROLASE activity.
Mild or moderate loss of motor function accompanied by spasticity in the lower extremities. This condition is a manifestation of CENTRAL NERVOUS SYSTEM DISEASES that cause injury to the motor cortex or descending motor pathways.
Acquired and inherited conditions that feature DYSTONIA as a primary manifestation of disease. These disorders are generally divided into generalized dystonias (e.g., dystonia musculorum deformans) and focal dystonias (e.g., writer's cramp). They are also classified by patterns of inheritance and by age of onset.
Nutritional factor found in milk, eggs, malted barley, liver, kidney, heart, and leafy vegetables. The richest natural source is yeast. It occurs in the free form only in the retina of the eye, in whey, and in urine; its principal forms in tissues and cells are as FLAVIN MONONUCLEOTIDE and FLAVIN-ADENINE DINUCLEOTIDE.
The methyl imidoester of suberic acid used to produce cross links in proteins. Each end of the imidoester will react with an amino group in the protein molecule to form an amidine.
An essential aromatic amino acid that is a precursor of MELANIN; DOPAMINE; noradrenalin (NOREPINEPHRINE), and THYROXINE.
Enzymes that catalyze the transfer of hydroxymethyl or formyl groups. EC 2.1.2.
A protozoan, previously also considered a fungus. Characteristics include sporangia that are stalked and multilobed. It is widely used in biomedical research.
The naturally occurring form of DIHYDROXYPHENYLALANINE and the immediate precursor of DOPAMINE. Unlike dopamine itself, it can be taken orally and crosses the blood-brain barrier. It is rapidly taken up by dopaminergic neurons and converted to DOPAMINE. It is used for the treatment of PARKINSONIAN DISORDERS and is usually given with agents that inhibit its conversion to dopamine outside of the central nervous system.
A free radical gas produced endogenously by a variety of mammalian cells, synthesized from ARGININE by NITRIC OXIDE SYNTHASE. Nitric oxide is one of the ENDOTHELIUM-DEPENDENT RELAXING FACTORS released by the vascular endothelium and mediates VASODILATION. It also inhibits platelet aggregation, induces disaggregation of aggregated platelets, and inhibits platelet adhesion to the vascular endothelium. Nitric oxide activates cytosolic GUANYLATE CYCLASE and thus elevates intracellular levels of CYCLIC GMP.
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.
A subclass of enzymes which includes all dehydrogenases acting on primary and secondary alcohols as well as hemiacetals. They are further classified according to the acceptor which can be NAD+ or NADP+ (subclass 1.1.1), cytochrome (1.1.2), oxygen (1.1.3), quinone (1.1.5), or another acceptor (1.1.99).
A CALCIUM-dependent, constitutively-expressed form of nitric oxide synthase found primarily in ENDOTHELIAL CELLS.
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.
An enzyme group with broad specificity. The enzymes decarboxylate a range of aromatic amino acids including dihydroxyphenylalanine (DOPA DECARBOXYLASE); TRYPTOPHAN; and HYDROXYTRYPTOPHAN.
Works containing information articles on subjects in every field of knowledge, usually arranged in alphabetical order, or a similar work limited to a special field or subject. (From The ALA Glossary of Library and Information Science, 1983)
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.
An NADPH-dependent enzyme that catalyzes the conversion of L-ARGININE and OXYGEN to produce CITRULLINE and NITRIC OXIDE.
Proteins produced by organs of the mother or the PLACENTA during PREGNANCY. These proteins may be pregnancy-specific (present only during pregnancy) or pregnancy-associated (present during pregnancy or under other conditions such as hormone therapy or certain malignancies.)
The hollow thick-walled muscular organ in the female PELVIS. It consists of the fundus (the body) which is the site of EMBRYO IMPLANTATION and FETAL DEVELOPMENT. Beyond the isthmus at the perineal end of fundus, is CERVIX UTERI (the neck) opening into VAGINA. Beyond the isthmi at the upper abdominal end of fundus, are the FALLOPIAN TUBES.
An amino acid produced in the urea cycle by the splitting off of urea from arginine.
The period of cyclic physiological and behavior changes in non-primate female mammals that exhibit ESTRUS. The estrous cycle generally consists of 4 or 5 distinct periods corresponding to the endocrine status (PROESTRUS; ESTRUS; METESTRUS; DIESTRUS; and ANESTRUS).
An autosomal recessive condition characterized by hypogonadism; spinocerebellar degeneration; MENTAL RETARDATION; RETINITIS PIGMENTOSA; and OBESITY. This syndrome was previously referred to as Laurence-Moon-Biedl syndrome until BARDET-BIEDL SYNDROME was identified as a distinct entity. (From N Engl J Med. 1989 Oct 12;321(15):1002-9)
Inorganic fluorides of tin. They include both stannic fluoride (tin tetrafluoride) and stannous fluoride (tin difluoride). The latter is used in the prevention of dental caries.
Sepsis associated with HYPOTENSION or hypoperfusion despite adequate fluid resuscitation. Perfusion abnormalities may include, but are not limited to LACTIC ACIDOSIS; OLIGURIA; or acute alteration in mental status.
An order of nematodes of the subclass SECERNENTEA. Its organisms possess two or three pairs of dorsolateral caudal papillae.
Infections with nematodes of the order ASCARIDIDA.
Strains of mice in which certain GENES of their GENOMES have been disrupted, or "knocked-out". To produce knockouts, using RECOMBINANT DNA technology, the normal DNA sequence of the gene being studied is altered to prevent synthesis of a normal gene product. Cloned cells in which this DNA alteration is successful are then injected into mouse EMBRYOS to produce chimeric mice. The chimeric mice are then bred to yield a strain in which all the cells of the mouse contain the disrupted gene. Knockout mice are used as EXPERIMENTAL ANIMAL MODELS for diseases (DISEASE MODELS, ANIMAL) and to clarify the functions of the genes.
Cell surface proteins that bind corticotropin-releasing hormone with high affinity and trigger intracellular changes which influence the behavior of cells. The corticotropin releasing-hormone receptors on anterior pituitary cells mediate the stimulation of corticotropin release by hypothalamic corticotropin releasing factor. The physiological consequence of activating corticotropin-releasing hormone receptors on central neurons is not well understood.
A peptide of about 41 amino acids that stimulates the release of ADRENOCORTICOTROPIC HORMONE. CRH is synthesized by neurons in the PARAVENTRICULAR NUCLEUS of the HYPOTHALAMUS. After being released into the pituitary portal circulation, CRH stimulates the release of ACTH from the PITUITARY GLAND. CRH can also be synthesized in other tissues, such as PLACENTA; ADRENAL MEDULLA; and TESTIS.
Neuropeptides of about 40 amino acids which are structurally similar to CORTICOTROPIN-RELEASING FACTOR. Unlike CRF acting primarily through type 1 CRF RECEPTORS, urocortins signal preferentially through type 2 CRF receptors. Urocortins have wide tissue distribution from fish to mammals, and diverse functions. In mammals, urocortins can suppress food intake, delays gastric emptying, and decreases heat-induced edema.
Bluish-colored region in the superior angle of the FOURTH VENTRICLE floor, corresponding to melanin-like pigmented nerve cells which lie lateral to the PERIAQUEDUCTAL GRAY.
Lipid-containing polysaccharides which are endotoxins and important group-specific antigens. They are often derived from the cell wall of gram-negative bacteria and induce immunoglobulin secretion. The lipopolysaccharide molecule consists of three parts: LIPID A, core polysaccharide, and O-specific chains (O ANTIGENS). When derived from Escherichia coli, lipopolysaccharides serve as polyclonal B-cell mitogens commonly used in laboratory immunology. (From Dorland, 28th ed)