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Studies on transcobalamin in cultured fibroblasts from patients with inborn errors of cobalamin metabolism

Cobalamin must be metabolized intracellularly in order to bind two enzymes: methionine synthase in cytoplasm and methylmalonyl-CoA mutase in mitochondria. Defects in this process cause different inborn errors of cobalamin metabolism (cblA-cblG and mut). A previous study described a cobalamin-binding protein, in addition to methylmalonyl-CoA mutase, in crude mitochondrial fractions. The amount of [57Co]cobalamin bound to this protein was increased in cblB, mut and cblD variant2 cell lines, compared to control cell lines. In the present study, this protein was identified as transcobalamin (TC). Mitochondrial fractions from a cblB cell line were incubated with anti-TC antibodies, which precipitated the cobalamin-bound protein. Analysis of mitochondrial and cytoplasmic fractions isolated from a chloroquine-incubated cblF cell line showed that isolated mitochondrial fractions contain lysosomal material, suggesting that the identified TC is lysosomal. Quantification of cobalamin-bound TC levels in whole cell extracts showed significant increases in cblB and mut groups compared to control cell lines.

Identiferoai:union.ndltd.org:LACETR/oai:collectionscanada.gc.ca:QMM.112320
Date January 2008
CreatorsYamani, Lama.
PublisherMcGill University
Source SetsLibrary and Archives Canada ETDs Repository / Centre d'archives des thèses électroniques de Bibliothèque et Archives Canada
LanguageEnglish
Detected LanguageEnglish
TypeElectronic Thesis or Dissertation
Formatapplication/pdf
CoverageMaster of Science (Department of Human Genetics.)
RightsAll items in eScholarship@McGill are protected by copyright with all rights reserved unless otherwise indicated.
Relationalephsysno: 002731695, proquestno: AAIMR51357, Theses scanned by UMI/ProQuest.

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