Cob(II)alamin reductase

In enzymology, a cobalamin reductase is an enzyme that catalyzes the chemical reaction
Thus, the two substrates of this enzyme are cob(I)alamin and NAD⁺, whereas its 3 products are cob(II)alamin, NADH, and H⁺.
This enzyme belongs to the family of oxidoreductases, specifically those oxidizing metal ion with NAD+ or NADP+ as acceptor. The systematic name of this enzyme class is cobalamin:NAD+ oxidoreductase. Other names in common use include vitamin B12r reductase, B12r reductase, and NADH2:cobalamin oxidoreductase. This enzyme participates in porphyrin and chlorophyll metabolism. It employs one cofactor, FAD.