Precorrin-6x reductase (IPR003723)

Short name: Precorrin-6x_reduct

Overlapping homologous superfamilies


Family relationships



Cobalamins (vitamin B12), both as deoxyadenosylcobalamin and methylcobalamin, are involved as cofactors in a variety of enzymatic reactions and are synthesized by some bacteria and archaea. About thirty enzymes are required to manufacture cobalamins, some of the most complex nonpolymeric molecules biosynthesized in the cell. Cobalamin biosynthesis can be divided into three distinct sections. The first results in the synthesis of the corrin ring component, cobinamide, from the ubiquitous tetrapyrrole primogenitor uroporphyrinogen III by a series of reactions including eight S-adenosyl-L- methionine-dependent methylations, ring contraction, cobalt chelation, decarboxylation, amidations, and 1-amino-2-propanol attachment. The second results in the synthesis of the lower axial ligand, dimethylbenzimidazole (DMB) and the third results in the assembly of the final coenzyme from the attachment of the corrin ring to the DMB as well as the addition of the upper coordinating ligand for the cobalt, either an adenosyl or a methyl group [PMID: 11215515].

The precorrin-6x reductase (EC: proteins cobK and cbiJ are involved in part I of the cobalamin biosynthesis pathway. They catalyses the NADPH-dependent reduction of precorrin-6x to a dihydro derivative named precorrin-6y [PMID: 1732193, PMID: 10559155].

GO terms

Biological Process

GO:0009236 cobalamin biosynthetic process
GO:0055114 oxidation-reduction process

Molecular Function

GO:0016994 precorrin-6A reductase activity

Cellular Component

No terms assigned in this category.

Contributing signatures

Signatures from InterPro member databases are used to construct an entry.
PROSITE profiles