Cobaltic protoporphyrin IX is a metalloporphyrin and an inducer of heme oxygenase-1 (HO-1) activity.¹Unlike other metalloporphyrins, cobaltic protoporphyrin IX induces activity of HO-1, the rate-limiting enzyme in heme catabolism,in vitroandin vivo.^1,2It also reduces the activity of δ-aminolevulinate synthase, the enzyme that catalyzes the rate-limiting step of heme biosynthesis, as well as decreases the activity of cytochrome P450 (CYP), in rat liver microsomesex vivowhen administered at a dose of 125 µmol/kg.²Cobaltic protoporphyrin IX (5 mg/kg) prevents liver injury and increases in the percentage of hepatic apoptotic cells in a mouse model of liver ischemia-reperfusion injury.³It increases survival and decreases the number of lung colony forming units (CFUs) in mice infected withY. pestisat the same dose.⁴Cobaltic protoporphyrin IX has also been used as a catalyst for the electrochemical reduction of carbon dioxide in carbon electrodes.⁵

1.Shan, Y., Lambrecht, R.W., Donohue, S.E., et al.Role of Bach1 and Nrf2 in up-regulation of the heme oxygenase-1 gene by cobalt protoporphyrinFASEB J.20(14)2651-2653(2006) 2.Drummond, G.S., and Kappas, A.The cytochrome P-450-depleted animal: An experimental model for in vivo studies in chemical biologyProc. Natl. Acad. Sci. USA79(7)2384-2388(1982) 3.Li, J., Wu, B., Teng, D., et al.Cobalt-protoporphyrin enhances heme oxygenase 1 expression and attenuates liver ischemia/reperfusion injury by inhibiting apoptosisMol. Med. Rep.17(3)4567-4572(2018) 4.Willix, J.L., Stockton, J.L., Olson, R.M., et al.Activation of heme oxygenase expression by cobalt protoporphyrin treatment prevents pneumonic plague caused by inhalation of Yersinia pestisAntimicrob. Agents Chemother.64(4)e01819-01819(2020) 5.Shen, J., Kortlever, R., Kas, R., et al.Electrocatalytic reduction of carbon dioxide to carbon monoxide and methane at an immobilized cobalt protoporphyrinNat. Commun.68177(2015)