This family consists of Precorrin-6x reductase EC:1.3.1.54. This enzyme catalyses the reaction: precorrin-6Y + NADP(+) <=> precorrin-6X + NADPH. CbiJ and CobK both catalyse the reduction of macocycle in the colbalmin biosynthesis pathway [1,2].

1: Cobalamin (vitamin B12) biosynthesis: identification and characterization of a Bacillus megaterium cobI operon. Raux E, Lanois A, Warren MJ, Rambach A, Thermes C; Biochem J 1998;335:159-166. PMID:9742225

2: Characterization of the cobalamin (vitamin B12) biosynthetic genes of Salmonella typhimurium. Roth JR, Lawrence JG, Rubenfield M, Kieffer-Higgins S, Church GM; J Bacteriol 1993;175:3303-3316. PMID:8501034