Biomaterial Database

Nitrous oxide exposure reduces hepatic C1-tetrahydrofolate synthase expression in rats. 1988

C K Barlowe, and D R Appling

Clayton Foundation Biochemical Institute, Department of Chemistry, University of Texas 78712.

C1-tetrahydrofolate synthase (C1-THF synthase) is a trifunctional enzyme which catalyzes the interconversion of one-carbon units attached to the coenzyme THF. Nitrous oxide (N2O) inhalation is known to inactivate hepatic cobalamin-dependent methionine synthase leading to methionine deficiency and trapping of THF in the methyl-THF form. Liver tissue from rats exposed to N2O for 48 hours exhibited a coordinate decrease in all three activities of C1-THF synthase of approximately 25%. A corresponding 25% decrease in immunoreactive C1-THF synthase was also observed after 48 hours. Thus, the decrease in the concentration of C1-THF synthase accounted entirely for the decreases observed in the three activities. These results suggest that perturbations of hepatic THF pools by N2O affect the level of C1-THF synthase expression at a translational or pretranslational level.

UI	MeSH Term	Description	Entries
D008025	Ligases	A class of enzymes that catalyze the formation of a bond between two substrate molecules, coupled with the hydrolysis of a pyrophosphate bond in ATP or a similar energy donor. (Dorland, 28th ed) EC 6.	Ligase,Synthetases,Synthetase
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
D008754	Methylenetetrahydrofolate Dehydrogenase (NADP)	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.	Methylenetetrahydrofolate Dehydrogenase (NADP+),Methylenetetrahydrofolate Dehydrogenase,Dehydrogenase, Methylenetetrahydrofolate
D009097	Multienzyme Complexes	Systems of enzymes which function sequentially by catalyzing consecutive reactions linked by common metabolic intermediates. They may involve simply a transfer of water molecules or hydrogen atoms and may be associated with large supramolecular structures such as MITOCHONDRIA or RIBOSOMES.	Complexes, Multienzyme
D009609	Nitrous Oxide	Nitrogen oxide (N2O). A colorless, odorless gas that is used as an anesthetic and analgesic. High concentrations cause a narcotic effect and may replace oxygen, causing death by asphyxia. It is also used as a food aerosol in the preparation of whipping cream.	Laughing Gas,Nitrogen Protoxide,Gas, Laughing,Oxide, Nitrous
D010088	Oxidoreductases	The class of all enzymes catalyzing oxidoreduction reactions. The substrate that is oxidized is regarded as a hydrogen donor. The systematic name is based on donor:acceptor oxidoreductase. The recommended name will be dehydrogenase, wherever this is possible; as an alternative, reductase can be used. Oxidase is only used in cases where O2 is the acceptor. (Enzyme Nomenclature, 1992, p9)	Dehydrogenases,Oxidases,Oxidoreductase,Reductases,Dehydrogenase,Oxidase,Reductase
D005574	Formate-Tetrahydrofolate Ligase	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.	Tetrahydrofolate Formylase,Formyltetrahydrofolate Synthetase,Formate Tetrahydrofolate Ligase,Formylase, Tetrahydrofolate,Ligase, Formate-Tetrahydrofolate,Synthetase, Formyltetrahydrofolate
D000619	Aminohydrolases
D000818	Animals	Unicellular or multicellular, heterotrophic organisms, that have sensation and the power of voluntary movement. Under the older five kingdom paradigm, Animalia was one of the kingdoms. Under the modern three domain model, Animalia represents one of the many groups in the domain EUKARYOTA.	Animal,Metazoa,Animalia