Studies on vitamin B12 metabolism in HeLa cells
| Autor: | Brian R. McAuslan, S.S. Kerwar, Herbert Weissbach, Carlos Spears |
|---|---|
| Rok vydání: | 1971 |
| Předmět: |
Vitamin
Biophysics Biochemistry Cell Line HeLa Tissue culture chemistry.chemical_compound Adenosine Triphosphate Folic Acid Methionine Transferases Culture Techniques Coenzyme A Vitamin B12 Isomerases Homocysteine Molecular Biology chemistry.chemical_classification Carbon Isotopes biology Methylmalonyl-CoA mutase Metabolism Carbon Dioxide biology.organism_classification Molecular biology Malonates Enzyme Activation Vitamin B 12 Enzyme chemistry Propionate Propionates HeLa Cells |
| Zdroj: | Archives of Biochemistry and Biophysics. 142:231-237 |
| ISSN: | 0003-9861 |
| DOI: | 10.1016/0003-9861(71)90279-7 |
| Popis: | In the present report some aspects of vitamin B 12 metabolism in HeLa cells and other tissue culture lines have been investigated. Mangum et al . (1) previously reported the presence of higher levels of N 5 -methyl- H 4 -folate-homocysteine transmethylase in tissue culture cells grown in the presence of vitamin B 12 . The present experiments indicate that under the growth conditions used, HeLa cells do not contain sufficient vitamin B 12 to satisfy the cobamide requirement of the transmethylase, and the increase in enzymatic activity that is observed when the cells are grown in the presence of vitamin B 12 results from the conversion of the apoenzyme form of the enzyme to active holoenzyme. No effect of the vitamin on the oxidation of propionate to CO 2 was observed in these cells suggesting that the amount of 5′-deoxyadenosyl B 12 (DBCC) present was sufficient so that the methylmalonyl CoA isomerase reaction was not rate limiting. Extracts of HeLa cells readily convert hydroxy-B 12 to DBCC in the presence of ATP and a reducing system. The optimum conditions for the enzymatic synthesis of DBCC are described. |
| Databáze: | OpenAIRE |
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