MMACHC decyanates CNCbl

Stable Identifier
R-HSA-3149519
Type
Reaction
Species
Homo sapiens
Compartment
Synonyms
MMACHC reductively decyanates CNCbl, 2 apo--(cyanocobalamin reductase) + 2 cyanocob(III)alamin + H(+) + NADPH => 2 cob(II)alamin--(cyanocobalamin reductase) + 2 hydrogen cyanide + NADP(+)
Locations in the PathwayBrowser
General
SVG |   | PPTX  | SBGN
Click the image above or here to open this reaction in the Pathway Browser
The layout of this reaction may differ from that in the pathway view due to the constraints in pathway layout

Cyanocobalamin (CNCbl), a semisynthetic molecule produced from bacterial hydroxocobalamin that is used in many pharmaceuticals and as a food additive, is one of the dietary cobalamins bound successively by TCN1, CBLIF, TCN2 and transported to cells throughout the body (Randaccio et al. 2010). In these cells, CNCbl is reductively decyanated by MMACHC (methylmalonic aciduria and homocystinuria type C protein) to produce cob(II)alamin (vitamin B12r) and hydrogen cyanide (HCN) (Kim et al. 2008), preparatory to its conversion to active cofactors methylcobalamin and adenosylcobalamin.

Literature References
PubMed ID Title Journal Year
18779575 Decyanation of vitamin B12 by a trafficking chaperone

Kim, J, Gherasim, C, Banerjee, R

Proc. Natl. Acad. Sci. U.S.A. 2008
20657474 Vitamin B12: unique metalorganic compounds and the most complex vitamins

Randaccio, L, Wuerges, J, Demitri, N, Geremia, S

Molecules 2010
21697092 Structural basis of multifunctionality in a vitamin B12-processing enzyme

Koutmos, M, Smith, JL, Gherasim, C, Banerjee, R

J Biol Chem 2011
Participants
Participates
Catalyst Activity

cyanocobalamin reductase (cyanide-eliminating) activity of MMACHC [cytosol]

Orthologous Events
Authored
Reviewed
Created
Cite Us!