Processing of glutathionylcobalamin by a bovine B-12 trafficking chaperone bCblC involved in intracellular B-12 metabolism

Title
Processing of glutathionylcobalamin by a bovine B-12 trafficking chaperone bCblC involved in intracellular B-12 metabolism
Author(s)
김지회정진주박지현박정호
Keywords
RAY CRYSTAL-STRUCTURE; METHYLMALONIC ACIDURIA; HUMAN-DISEASES; GLUTATHIONE; IDENTIFICATION; BINDING; HOMOCYSTINURIA; VITAMIN-B-12; COBALAMINS; PROTEIN
Issue Date
201401
Publisher
ACADEMIC PRESS INC ELSEVIER SCIENCE
Citation
BIOCHEMICAL AND BIOPHYSICAL RESEARCH COMMUNICATIONS, v.443, no.1, pp.173 - 178
Abstract
Glutathionylcobalamin (GSCbl) is a biologically relevant vitamin B-12 derivative and contains glutathione as the upper axial ligand thought formation of a cobalt-sulfur bond. GSCbl has been shown to be an effective precursor of enzyme cofactors, however processing of the cobalamin in intracellular B-12 metabolism has not been fully elucidated. In this study, we discovered that bCblC, a bovine B-12 trafficking chaperone, catalyzes elimination of the glutathione ligand from GSCbl by using the reduced form of glutathione (GSH). Deglutathionylation products are base-off cob(II)alamin and glutathione disulfide, which are generated stoichiometrically to GSH. Although cob(I)alamin was not detected due to its instability, deglutathionylation is likely analogous to dealkylation of alkylcobalamins, which uses the thiolate of GSH for nucleophilic displacement. The catalytic turnover number for the deglutathionylation of GSCbl is >= 1.62 +/- 0.13 min(-1), which is, at least, an order of magnitude higher than that for elimination of upper axial ligands from other cobalamins. Considering the prevalence of GSH at millimolar concentrations in cells, our results explain the previous finding that GSCbl is more effective than other cobalamins for synthesis of enzyme cofactors. (C) 2013 Elsevier Inc. All rights reserved.
URI
http://hdl.handle.net/YU.REPOSITORY/33527http://dx.doi.org/10.1016/j.bbrc.2013.11.075
ISSN
0006-291X
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생명공학부 > 생명공학부 > Articles
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