Several of the inborn errors of vitamin B$ sb{12}$ (cobalamin, Cbl) metabolism (cblC, cblD, cblE, cblF, cblG) are associated with homocystinuria and hypomethioninemia due to a functional deficiency of the cytoplasmic enzyme methionine synthase which requires methylcobalamin (MeCbl) as a cofactor. We compared the growth of cultured fibroblasts from controls with those from patients with a selective deficiency of MeCbl (cblE and cblG) and with those from patients with a defect in both MeCbl and adenosylcobalamin (AdoCbl) (cblC, cblD and cblF). Cells were grown in methionine and folic acid free media and in fully supplemented medium. Control cells were able to grow in the deficient medium supplied with homocysteine, cobalamin and folate, while mutant cells were not, due to their inability to synthesize methionine from its immediate metabolic precursor, homocysteine. This differential growth is useful for screening for genetic defects of methionine biosynthesis. Moreover, by correcting methionine auxotrophy in these cells, it may be possible to isolate genes which code for the products that are deficient in these disorders.
| Identifer | oai:union.ndltd.org:LACETR/oai:collectionscanada.gc.ca:QMM.56756 |
| Date | January 1992 |
| Creators | Kocic, Vesna Garovic |
| Publisher | McGill University |
| Source Sets | Library and Archives Canada ETDs Repository / Centre d'archives des thèses électroniques de Bibliothèque et Archives Canada |
| Language | English |
| Detected Language | English |
| Type | Electronic Thesis or Dissertation |
| Format | application/pdf |
| Coverage | Master of Science (Department of Biology.) |
| Rights | All items in eScholarship@McGill are protected by copyright with all rights reserved unless otherwise indicated. |
| Relation | alephsysno: 001318397, proquestno: AAIMM80475, Theses scanned by UMI/ProQuest. |
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