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This Article Full Text (PDF) Alert me when this article is cited Alert me if a correction is posted Services Email this article to a friend Similar articles in this journal Similar articles in PubMed Alert me to new issues of the journal Download to citation manager Rights and Permissions Citing Articles Citing Articles via HighWire Citing Articles via CrossRef Citing Articles via Google Scholar Google Scholar Articles by Quadros, E. V. Articles by Linnell, J. C. Search for Related Content PubMed PubMed Citation Articles by Quadros, E. V. Articles by Linnell, J. C. Social Bookmarking                   What's this?  Previous Article  |  Table of Contents  |  Next Article  Synthesis of cobalamin coenzymes by human lymphocytes in vitro and the effect of folates and metabolic inhibitors EV Quadros, DM Matthews, AV Hoffbrand and JC Linnell The uptake of 57Co-cyanocobalamin (CN-Cbl) and its conversion to 5- deoxyadenosylcobalamin (Ado-Cbl), methylcobalamin (Me-Cbl), and hydroxocobalamin (OH-Cbl) has been studied in phytohemagglutinin (PHA)- transformed lymphocytes from normal subjects and patients with patients with pernicious anemia. Uptake and conversion were much greater by PHA- stimulated lymphocytes than by mature non-transformed lymphocytes. In normal cells, uptake of 57Co-CN-Cbl and synthesis of the cobalamin coenzymes were approximately linear between 3 and 48 hr incubation. Ado- Cbl was the major cobalamin formed, and after 72 hr the cells contained about twice as much Ado-Cbl as Me-Cbl. Uptake by lymphocytes from patients with untreated pernicious anemia (PA) was greater than that by normal lymphocytes, but the proportions of Ado-Cbl and Me-Cbl synthesized by each were similar. Folic acid and methyltetrahydrofolate enhanced synthesis of Me-Cbl both in normal and in PA cells, while methotrexate and 5-fluorouracil depressed it. This depression was overcome by 5-formyltetrahydrofolate, suggesting that an uninterrupted folate cycle may play an important role in Me-Cbl synthesis. Volume 48, Issue 4, pp. 609-619, 10/01/1976 Copyright © 1976 by The American Society of Hematology CiteULike    Connotea    Del.icio.us    Digg    Reddit    Technorati    What's this? This article has been cited by other articles: T. Fiskerstrand, P. M. Uel, and a. H. Refsum Folate Depletion Induced by Methotrexate Affects Methionine Synthase Activity and Its Susceptibility to Inactivation by Nitrous Oxide J. Pharmacol. Exp. Ther., September 1, 1997; 282(3): 1305 - 1311. [Abstract] [Full Text]

	Copyright © 1976 by American Society of Hematology         Online ISSN: 1528-0020