N5-methyltetrahydrofolate: homocysteine methyltransferase activity in extracts from normal, malignant and embryonic tissue culture cells
| Autor: | Roberts A. Smith, Barbara C. Halpern, D. Hardy, Hilary Ashe, Richard M. Halpern, Brian R. Clark, Fred Chu |
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| Rok vydání: | 1974 |
| Předmět: |
Homocysteine
Biophysics Thymus Gland Biochemistry chemistry.chemical_compound Tissue culture Mice Methionine Carcinosarcoma Culture Techniques Animals Humans Cyanocobalamin Vitamin B12 Methionine synthase Amnion Carbon Radioisotopes Leukemia L1210 Molecular Biology Cells Cultured Tetrahydrofolates biology Homocystine Cell Biology Embryonic Tissue Methyltransferases Fibroblasts Chromatography Ion Exchange Rats chemistry Liver Leukemia Myeloid biology.protein Monocytic leukemia |
| Zdroj: | Biochemical and biophysical research communications. 57(2) |
| ISSN: | 0006-291X |
| Popis: | Malignant cells (J111, L1210, W-256) and human embryonic cells (FL) are unable to survive and grow when homocystine replaces methionine in tissue culture media containing excess vitamin B12 and folic acid. Extracts of these same cells when grown in media containing methionine and more than adequate vitamin B12 and folic acid have diminished N5-methyltetrahydrofolate: homocysteine methyltransferase activities in the absence of added cyanocobalamin when compared with extracts of normal cells (adult rat thymus and liver fibroblasts). Extracts of human monocytic leukemia (J111) and human amnion cells (FL) have normal enzymatic activity in the presence of added cyanocobalamin whereas the rodent malignant cells (W-256 and L1210) have abnormally low activity in the absence or presence of added vitamin B12. |
| Databáze: | OpenAIRE |
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