Reactome | MMACHC decyanates CNCbl

MMACHC decyanates CNCbl

Stable Identifier

R-HSA-3149519

Type

Reaction

Species

Homo sapiens

Compartment

cytosol

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(+)

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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 B_12r) 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