EC 2.5.1.151 - Alkylcobalamin dealkylase

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IntEnz Enzyme Nomenclature
EC 2.5.1.151

Names

Accepted name:
alkylcobalamin dealkylase
Systematic name:
alkylcobalamin:glutathione S-alkyltransferase

Reaction

Comments:

This mammalian enzyme, which is cytosolic, can bind internalized alkylcobalamins and process them to cob(I)alamin using the thiolate of glutathione for nucleophilic displacement. The product remains bound to the protein, and, following its oxidation to cob(II)alamin, is transferred by the enzyme, together with its interacting partner MMADHC, directly to downstream enzymes involved in adenosylcobalamin and methylcobalamin biosynthesis. In addition to its dealkylase function, the enzyme also catalyse an entirely different decyanase reaction with cyanocobalamin [cf. EC 1.16.1.6, cyanocobalamin reductase (cyanide-eliminating)].

Links to other databases

Enzymes and pathways: NC-IUBMB , BRENDA , ExplorEnz , ENZYME@ExPASy , KEGG , MetaCyc , UniPathway
Structural data: CSA , EC2PDB

References

  1. Hannibal, L., Kim, J., Brasch, N. E., Wang, S., Rosenblatt, D. S., Banerjee, R., Jacobsen, D. W.
    Processing of alkylcobalamins in mammalian cells: A role for the MMACHC (cblC) gene product.
    Mol. Genet. Metab. 97: 260-266 (2009). [PMID: 19447654]
  2. Kim, J., Hannibal, L., Gherasim, C., Jacobsen, D. W., Banerjee, R.
    A human vitamin B12 trafficking protein uses glutathione transferase activity for processing alkylcobalamins.
    J. Biol. Chem. 284: 33418-33424 (2009). [PMID: 19801555]
  3. Koutmos, M., Gherasim, C., Smith, J. L., Banerjee, R.
    Structural basis of multifunctionality in a vitamin B12-processing enzyme.
    J. Biol. Chem. 286: 29780-29787 (2011). [PMID: 21697092]

[EC 2.5.1.151 created 2018]