Siroheme is an organic compound with the chemical formula C42H46N4O16. Siroheme belongs to the tetrapyrroles and derivatives, a class of organoheterocyclic compounds within the organic compounds. With an average molecular weight of 914.64 g/mol, Siroheme is a heavy molecule. In biological systems, it has one recorded protein target, which is the sulfite reductase [NADPH] hemoprotein beta-component (cysI).