3d image of siroheme skeletal formula

siroheme sirohaem heme-like prosthetic group enzyme six-electron reduction sulfur nitrogen sulfite reductase sulfur assimilation pathway sulfite sulfide homocysteine tetrapyrroles macrocyclic ligand uroporphyrinogen iii dihydrosirohydrochlorin sirohydrochlorin macrocycle metabolite metabolism biosynthesis cycle mechanism path biosynthetic intermediate biogenesis substrate precursor synthesis derivative bioprecursor metabolic endogenous biochemistry biomolecule bioactive biochemical molecule molecular formula skeletal structural structure 3d