1.14.13.83 additional information biosynthesis of vitamin B12 1.14.13.83 additional information the enzyme is involved in the mechanism of the ring contraction process during vitamin B12 biosynthesis, comparison to the ring contraction process reaction pathway under anaerobic conditions in Propionibacterium freudenreichii ssp. shermanii, overview 1.14.13.83 precorrin-3 + NADH + H+ + O2 biosynthesis of vitamin B12, part of the ring contractase system for oxidative ring contraction 1.14.13.83 precorrin-3A + NADH + H+ + O2 biosynthesis of vitamin B12 1.14.13.83 precorrin-3A + NADH + H+ + O2 pathway to coenzyme B12, biosynthesis of the corrin macrocycle, catalyzes a complex oxidative reaction involving C20 hydroxylation and gamma-lactone formation from ring-A acetate to C1 1.14.13.83 precorrin-3A + NADH + H+ + O2 first step in the aerobic pathway of viamin B12 biosynthesis 1.14.13.83 precorrin-3A + NADH + H+ + O2 the Brucella melitensis enzyme is fully active in vitro (20 mM Tris-HCl buffer, pH 8.0, with 100 mM NaCl, S-adenosyl-L-methionine (SAM), 5-aminolevulinic acid (ALA) and NADPH, aerobic, dark, 4°C) and the mononuclear non-heme iron is reducible by dithionite and then is able to react with NO as oxygen analogue in the presence of the substrate 1.14.13.83 precorrin-3A + NADH + H+ + O2 the Pseudomonas denitrificans enzyme is active in vivo but inactive in vitro (20 mM Tris-HCl buffer, pH 8.0, with 100 mM NaCl, S-adenosyl-L-methionine (SAM), 5-aminolevulinic acid (ALA) and NADPH, aerobic, dark, 4°C), the mononuclear non-heme iron is not reducible and probably rapidly inactivated outside the bacterium 1.14.13.83 precorrin-3A + NADH + O2 - 1.14.13.83 precorrin-3A + NADH + O2 the enzyme is involved in ring contraction, whereby an integral carbon atom of the tetrapyrrole-derived macrocycle is removed, and cobalt chelation during aerobic synthesis of vitamin B12, the catalytic cycle of CobZ, overview