Effect of 4-hydroxypyrazole on tryptophan and formate metabolism in isolated rat liver cells
| Autor: | J S Cook, C I Pogson |
|---|---|
| Rok vydání: | 1982 |
| Předmět: |
Male
Formates Stimulation In Vitro Techniques Biology Biochemistry Formate oxidation chemistry.chemical_compound Methionine In vivo Animals Formate Molecular Biology Tryptophan Rats Inbred Strains Cell Biology Carbon Dioxide Tryptophan Oxygenase Glycolates Rats Liver chemistry Catalase Depression Chemical biology.protein Pyrazoles Flux (metabolism) Research Article |
| Zdroj: | Biochemical Journal. 204:307-312 |
| ISSN: | 0264-6021 |
| DOI: | 10.1042/bj2040307 |
| Popis: | 1. 4-Hydroxypyrazole inhibits flux through tryptophan 2.3-dioxygenase in cells. The inhibition is apparently non-competitive with Ki = 0.15 mM. 2. Hydroxypyrazole inhibits the oxidation of formate to CO2 in liver cells. 3. Glycollate, which generates H2O2, stimulates formate oxidation. This process is inhibited by 4-hydroxypyrazole. 4. Methionine stimulates formate oxidation in cells and this stimulation is insensitive to 4-hydroxypyrazole. 5. It is concluded that, in freshly isolated liver cells, formate oxidation proceeds by a pathway involving catalase. In vivo, or when methionine is added to cell incubations, the pathway of oxidation involves tetrahydrofolate, and is insensitive to catalase inhibitors. 6. Methionine at physiological concentrations inhibits the activity of tryptophan 2,3-dioxygenase in isolated liver cells. |
| Databáze: | OpenAIRE |
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