These tools will no longer be maintained as of December 31, 2024. Archived website can be found here. PubMed4Hh GitHub repository can be found here. Contact NLM Customer Service if you have questions.


Pubmed for Handhelds

PUBMED FOR HANDHELDS

Search MEDLINE/PubMed

  • Title: Utilization of preformed and endogenously synthesized methionine by cells in tissue culture.
    Author: Tisdale MJ.
    Journal: Br J Cancer; 1984 Mar; 49(3):315-20. PubMed ID: 6704306.
    Abstract:
    Some malignant and transformed cell lines are unable to proliferate in vitro in a L-methionine-depleted medium supplemented with L-homocysteine. To investigate the utilization of preformed and endogenously synthesized methionine 4 cell lines have been chosen with a range of abilities to proliferate under such nutritional conditions. The order of the ability of these cell lines to proliferate in an L-methionine-depleted medium containing 0.1 mM L-homocysteine parallels the minimal concentration of L-methionine required for optimal growth; L-methionine auxotrophs having a greater minimal requirement. In the presence of 0.1 mM L-homocysteine all of the cell lines synthesize macromolecules from [5-14C]methyltetrahydrofolic acid during a 24 h period, and the cell line with the highest methionine requirement shows the most extensive incorporation of radiolabel into DNA and RNA, both in depleted medium and in medium containing 6.7 microM L-methionine. Double-label experiments using [5-14C]methyltetrahydrofolic acid and L-(methyl-3H) methionine show preferential incorporation of preformed over endogenously synthesized methionine by methionine auxotrophs. There is no alteration in the intracellular level of S-adenosyl-L-homocysteine (SAH) or SAH hydrolase activity in cells incubated for 24 h in methionine-depleted medium supplemented with 0.1 mM L-homocysteine. These results suggest that certain cell lines are unable to effectively use endogenously synthesized methionine.
    [Abstract] [Full Text] [Related] [New Search]