Cyanocobalamin reductase (cyanide-eliminating)

In enzymology, a cyanocobalamin reductase is an enzyme that catalyzes the chemical reaction
The 3 substrates of this enzyme are cob(I)alamin, cyanide, and NADP⁺, whereas its 3 products are cyanocob(III)alamin, NADPH, and H⁺.
This enzyme belongs to the family of oxidoreductases, specifically those that oxidize metal ions and use NAD+ or NADP+ as an electron acceptor. The systematic name of this enzyme class is cobalamin, cyanide:NADP+ oxidoreductase. Other names in common use include cyanocobalamin reductase, cyanocobalamin reductase , cyanocobalamin reductase , and NADPH:cyanocobalamin oxidoreductase . This enzyme participates in porphyrin and chlorophyll metabolism. It uses one cofactor, FAD.
Humans have one gene producing a protein with this enzymatic activity, MMACHC. This enzyme also has alkylcobalamin reductase activity.