KEGG   ENZYME: 1.16.1.6Help
Entry
EC 1.16.1.6                 Enzyme                                 

Name
cyanocobalamin reductase (cyanide-eliminating);
MMACHC (gene name);
CblC;
cyanocobalamin reductase;
cyanocobalamin reductase (NADPH, cyanide-eliminating);
cyanocobalamin reductase (NADPH, CN-eliminating);
NADPH:cyanocob(III)alamin oxidoreductase (cyanide-eliminating);
cob(I)alamin, cyanide:NADP+ oxidoreductase
Class
Oxidoreductases;
Oxidizing metal ions;
With NAD+ or NADP+ as acceptor
BRITE hierarchy
Sysname
cob(II)alamin, hydrogen cyanide:NADP+ oxidoreductase
Reaction(IUBMB)
2 cob(II)alamin-[cyanocobalamin reductase] + 2 hydrogen cyanide + NADP+ = 2 cyanocob(III)alamin + 2 [cyanocobalamin reductase] + NADPH + H+ [RN:R02999]
Reaction(KEGG)
Substrate
cob(II)alamin-[cyanocobalamin reductase];
hydrogen cyanide [CPD:C01326];
NADP+ [CPD:C00006]
Product
cyanocob(III)alamin [CPD:C02823];
[cyanocobalamin reductase];
NADPH [CPD:C00005];
H+ [CPD:C00080]
Comment
The mammalian enzyme, which is cytosolic, can bind internalized cyanocobalamin and process it to cob(II)alamin by removing the upper axial ligand. The product remains bound to the protein, which, together with its interacting partner MMADHC, transfers it directly to downstream enzymes involved in adenosylcobalamin and methylcobalamin biosynthesis. In addition to its decyanase function, the mammalian enzyme also catalyses an entirely different chemical reaction with alkylcobalamins, using the thiolate of glutathione for nucleophilic displacement, generating cob(I)alamin and the corresponding glutathione thioether (cf. EC 2.5.1.151, alkylcobalamin dealkylase).
History
EC 1.16.1.6 created 1989 as EC 1.6.99.12, transferred 2002 to EC 1.16.1.6, modified 2018
Pathway
ec00860  Porphyrin and chlorophyll metabolism
ec01100  Metabolic pathways
Orthology
K14618  cyanocobalamin reductase (cyanide-eliminating) / alkylcobalamin dealkylase
Genes
HSA: 25974(MMACHC)
PTR: 469180(MMACHC)
PPS: 100968335(MMACHC)
GGO: 101152807(MMACHC)
PON: 100455100(MMACHC)
NLE: 100580574(MMACHC)
MCC: 706247(MMACHC)
MCF: 102121304(MMACHC)
CSAB: 103224912(MMACHC)
RRO: 104662137(MMACHC)
RBB: 108535651(MMACHC)
CJC: 100399324(MMACHC)
SBQ: 101027482(MMACHC)
MMU: 67096(Mmachc)
RNO: 313520(Mmachc)
CGE: 100751045(Mmachc)
NGI: 103737785(Mmachc)
HGL: 101709397(Mmachc)
OCU: 100347413(MMACHC)
TUP: 102472726(MMACHC)
CFA: 482514(MMACHC)
AML: 100466484(MMACHC)
UMR: 103670776(MMACHC)
ORO: 101379031(MMACHC)
FCA: 101090955(MMACHC)
PTG: 102954225(MMACHC)
AJU: 106970243(MMACHC)
BTA: 513433(MMACHC)
BOM: 102277584(MMACHC)
BIU: 109556357(MMACHC)
PHD: 102328935(MMACHC)
CHX: 102183931(MMACHC)
OAS: 101120707(MMACHC)
SSC: 100513159(MMACHC)
CFR: 102509232(MMACHC)
CDK: 105090870(MMACHC)
BACU: 103014111(MMACHC)
LVE: 103075700(MMACHC)
OOR: 101274733(MMACHC)
ECB: 100065336(MMACHC)
EPZ: 103551877(MMACHC)
EAI: 106826139(MMACHC)
MYB: 102260677(MMACHC)
MYD: 102764382(MMACHC)
HAI: 109375517(MMACHC)
RSS: 109456881(MMACHC)
PALE: 102888849(MMACHC)
LAV: 100673499(MMACHC)
TMU: 101353030
MDO: 100024700(MMACHC)
SHR: 100914568(MMACHC)
OAA: 100077154(MMACHC) 100084824
GGA: 424597(MMACHC)
MGP: 100547376(MMACHC)
CJO: 107317442(MMACHC)
APLA: 101804029(MMACHC)
ACYG: 106033094(MMACHC)
TGU: 105759460(MMACHC)
SCAN: 103815175(MMACHC)
GFR: 102038500(MMACHC)
FAB: 101815080(MMACHC)
PHI: 102110636(MMACHC)
PMAJ: 107208008(MMACHC)
CCAE: 111933112(MMACHC)
CCW: 104695241(MMACHC)
FPG: 101914760(MMACHC)
FCH: 102058033(MMACHC)
CLV: 102088492(MMACHC)
EGZ: 104126262(MMACHC)
NNI: 104015417(MMACHC)
ACUN: 113482722(MMACHC)
AAM: 106485930(MMACHC)
ASN: 102383499(MMACHC)
AMJ: 102560477(MMACHC)
PSS: 102459461(MMACHC)
CMY: 102936214(MMACHC)
CPIC: 101952441(MMACHC)
ACS: 100552851(mmachc)
PVT: 110073759(MMACHC)
PBI: 103063544(MMACHC)
PMUR: 107283422(MMACHC)
GJA: 107107920(MMACHC)
XLA: 100127331(mmachc.L)
XTR: 549685(mmachc)
NPR: 108800338(MMACHC)
DRE: 555267(mmachc)
SRX: 107757670(mmachc)
SANH: 107653140(mmachc)
SGH: 107565041(mmachc)
CCAR: 109051604(mmachc)
IPU: 100528283(mmachc)
PHYP: 113546876(mmachc)
AMEX: 103032715(mmachc)
EEE: 113591323(mmachc)
TRU: 101073402(mmachc)
LCO: 104926001(mmachc)
NCC: 104967760(mmachc)
MZE: 101475866(mmachc)
OLA: 101155593(mmachc)
XMA: 102223263(mmachc)
PRET: 103463749(mmachc)
NFU: 107396398(mmachc)
KMR: 108230696(mmachc)
CSEM: 103376733(mmachc)
LCF: 108879008(mmachc)
SDU: 111231994(mmachc)
HCQ: 109532243(mmachc)
BPEC: 110154834(mmachc)
MALB: 109974876(mmachc)
SASA: 100196847(mmachc)
OTW: 112251067(mmachc)
SALP: 111975270(mmachc)
ELS: 105011679(mmachc)
SFM: 108923522(mmachc)
PKI: 111834817(mmachc)
LCM: 102353117(MMACHC)
CMK: 103182780(mmachc)
CIN: 100181296
SPU: 575015
APLC: 110989375
SKO: 100368262
FCD: 110861518
DPTE: 113791070
CEL: CELE_ZK546.17(cblc-1)
CBR: CBG02282(Cbr-mdt-4)
TSP: Tsp_00699
CRG: 105331412
MYI: 110443657
LAK: 106178486
SHX: MS3_11205
EPA: 110237339
ADF: 107347741
PDAM: 113667854
SPIS: 111334144
HMG: 100212172
AQU: 100641773
 » show all
Taxonomy
Reference
1  [PMID:3134526]
  Authors
Watanabe F, Oki Y, Nakano Y, Kitaoka S.
  Title
Occurrence and characterization of cyanocobalamin reductase (NADPH; CN-eliminating) involved in decyanation of cyanocobalamin in Euglena gracilis.
  Journal
J Nutr Sci Vitaminol (Tokyo) 34:1-10 (1988)
Reference
2  [PMID:18779575]
  Authors
Kim J, Gherasim C, Banerjee R
  Title
Decyanation of vitamin B12 by a trafficking chaperone.
  Journal
Proc Natl Acad Sci U S A 105:14551-4 (2008)
DOI:10.1073/pnas.0805989105
Reference
3  [PMID:21697092]
  Authors
Koutmos M, Gherasim C, Smith JL, Banerjee R
  Title
Structural basis of multifunctionality in a vitamin B12-processing enzyme.
  Journal
J Biol Chem 286:29780-7 (2011)
DOI:10.1074/jbc.M111.261370
Reference
4  [PMID:23270877]
  Authors
Mah W, Deme JC, Watkins D, Fung S, Janer A, Shoubridge EA, Rosenblatt DS, Coulton JW
  Title
Subcellular location of MMACHC and MMADHC, two human proteins central to intracellular vitamin B(12) metabolism.
  Journal
Mol Genet Metab 108:112-8 (2013)
DOI:10.1016/j.ymgme.2012.11.284
Other DBs
ExplorEnz - The Enzyme Database: 1.16.1.6
IUBMB Enzyme Nomenclature: 1.16.1.6
ExPASy - ENZYME nomenclature database: 1.16.1.6
BRENDA, the Enzyme Database: 1.16.1.6
CAS: 131145-00-1

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