Cobalt chelatase (EC 6.6.1.2) is an enzyme that catalyzes the chemical reaction The four substrates of this enzyme are ATP, hydrogenobyrinic acid a,c-diamide, Co2+, and H2O; its four products are ADP, phosphate, cob(II)yrinic acid a,c-diamide, and H+.

[5] CobT, too, has been found to be remotely related to the third subunit of Mg-chelatase, BchD (involved in bacteriochlorophyll synthesis, e.g., in Rhodobacter capsulatus).

[5] This enzyme belongs to the family of ligases, specifically those forming nitrogen-D-metal bonds in coordination complexes.

The systematic name of this enzyme class is hydrogenobyrinic-acid-a,c-diamide:cobalt cobalt-ligase (ADP-forming).

Other names in common use include hydrogenobyrinic acid a,c-diamide cobaltochelatase, CobNST, and CobNCobST.