Zinc Protoporphyrin-9

Zinc protoporphyrin-9 is a potent, selective heme oxygenase inhibitor, interleukin-1 antagonist, GCS inhibitor, and NOS1, NOS2, and NOS3 inhibitor. Heme oxygenase catalyzes heme degradation to produce CO, which is an activator of guanylyl cyclase and shares some chemical and biological properties of NO. Zinc protoporphyrin-9 exhibits a time- and concentration-dependent inactivation of all three isoforms of nitric oxide synthase (IC₅₀=0.8μM, 4.0μM, and 5.0μM for NOS1, NOS2 and NOS3, respectively). In olfactory neuronal cultures, this product has been used to block CO biosynthesis, which lowered cGMP concentrations. Zinc protoporphyrin-9 is an extremely useful tool to elucidate the role of CO in signal transduction and as a neurotransmitter. Copper(II) Protoporphyrin IX (free acid) can be used as a negative control in heme oxygenase studies.