Biomaterial Database

Guanosine triphosphate cyclohydrolase activity in rat tissues. 1984

Z Bellahsene, and J L Dhondt, and J P Farriaux

The GTP cyclohydrolase activity of rat tissues has been studied by means of the measurement of formic acid release and neopterin synthesis from GTP. After gel filtration of a 45%-satd.-(NH4)2SO4 fraction of liver homogenates, three enzyme fractions were separated and named A1, A2 and A3 according to the order of their elution. Fractions A1 and A3 displayed an 8-formyl-GTP deformylase activity; no proof of cyclized product has yet been established. This activity was heat-labile and required Mg2+ for maximal activity. Fraction A2 displayed a 'neopterin-synthetase' activity, with dihydroneopterin triphosphate and formic acid formed in stochiometric amounts. Fraction A1 isolated from heat-treated homogenates also produced dihydroneopterin triphosphate. Neopterin synthetase activity in fractions A1 and A2 was heat-resistant and inhibited by Mg2+. In liver the A2 fraction represented 70-75% of the neopterin synthetase capacity and was inhibited by reduced pterines (sepiapterin, dihydrobiopterin and tetrahydrobiopterin) and to a lesser extent by reduced forms of folic acid. In kidney and brain, fraction A1 and A3 GTP 8-formylhydrolase activities were found in significant amounts, in contrast with the neopterin synthetase activity, which was low and appeared to be confined to the A1 fraction.

UI	MeSH Term	Description	Entries
D007668	Kidney	Body organ that filters blood for the secretion of URINE and that regulates ion concentrations.	Kidneys
D008099	Liver	A large lobed glandular organ in the abdomen of vertebrates that is responsible for detoxification, metabolism, synthesis and storage of various substances.	Livers
D008297	Male		Males
D008956	Models, Chemical	Theoretical representations that simulate the behavior or activity of chemical processes or phenomena; includes the use of mathematical equations, computers, and other electronic equipment.	Chemical Models,Chemical Model,Model, Chemical
D011621	Pteridines	Compounds based on pyrazino[2,3-d]pyrimidine which is a pyrimidine fused to a pyrazine, containing four NITROGEN atoms.	1,3,5,8-Tetraazanaphthalene,Pteridine,Pteridinone,Pyrazino(2,3-d)pyrimidine,Pyrazinopyrimidine,Pyrazinopyrimidines,Pyrimido(4,5-b)pyrazine,Pteridinones
D011919	Rats, Inbred Strains	Genetically identical individuals developed from brother and sister matings which have been carried out for twenty or more generations or by parent x offspring matings carried out with certain restrictions. This also includes animals with a long history of closed colony breeding.	August Rats,Inbred Rat Strains,Inbred Strain of Rat,Inbred Strain of Rats,Inbred Strains of Rats,Rat, Inbred Strain,August Rat,Inbred Rat Strain,Inbred Strain Rat,Inbred Strain Rats,Inbred Strains Rat,Inbred Strains Rats,Rat Inbred Strain,Rat Inbred Strains,Rat Strain, Inbred,Rat Strains, Inbred,Rat, August,Rat, Inbred Strains,Rats Inbred Strain,Rats Inbred Strains,Rats, August,Rats, Inbred Strain,Strain Rat, Inbred,Strain Rats, Inbred,Strain, Inbred Rat,Strains, Inbred Rat
D001921	Brain	The part of CENTRAL NERVOUS SYSTEM that is contained within the skull (CRANIUM). Arising from the NEURAL TUBE, the embryonic brain is comprised of three major parts including PROSENCEPHALON (the forebrain); MESENCEPHALON (the midbrain); and RHOMBENCEPHALON (the hindbrain). The developed brain consists of CEREBRUM; CEREBELLUM; and other structures in the BRAIN STEM.	Encephalon
D002850	Chromatography, Gel	Chromatography on non-ionic gels without regard to the mechanism of solute discrimination.	Chromatography, Exclusion,Chromatography, Gel Permeation,Chromatography, Molecular Sieve,Gel Filtration,Gel Filtration Chromatography,Chromatography, Size Exclusion,Exclusion Chromatography,Gel Chromatography,Gel Permeation Chromatography,Molecular Sieve Chromatography,Chromatography, Gel Filtration,Exclusion Chromatography, Size,Filtration Chromatography, Gel,Filtration, Gel,Sieve Chromatography, Molecular,Size Exclusion Chromatography
D005561	Formates	Derivatives of formic acids. Included under this heading are a broad variety of acid forms, salts, esters, and amides that are formed with a single carbon carboxy group.	Formic Acids,Acids, Formic
D006136	GTP Cyclohydrolase	(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 3.5.4.16 (GTP cyclohydrolase I) and EC 3.5.4.25 (GTP cyclohydrolase II).	GTP 8-Formylhydrolase,GTP Dihydrolase,GTP Ring-Opening Enzyme,7,8-Dihydroneopterintriphosphate Synthetase,GTP Cyclohydrolase I,GTP Cyclohydrolase II,7,8 Dihydroneopterintriphosphate Synthetase,8-Formylhydrolase, GTP,Cyclohydrolase I, GTP,Cyclohydrolase II, GTP,Cyclohydrolase, GTP,Dihydrolase, GTP,GTP 8 Formylhydrolase,GTP Ring Opening Enzyme,Ring-Opening Enzyme, GTP,Synthetase, 7,8-Dihydroneopterintriphosphate