Heme oxygenase-1 (HO-1), also known as heat shock protein 32 (Hsp32), is an inducible heme oxygenase encoded by the HMOX1 gene. It is a membrane-bound enzyme that catalyzes the cleavage of heme to release carbon monoxide (CO), ferrous ions (Fe2+), and biliverdin, with biliverdin being further processed into bilirubin. HO-1 is found in human spleen, liver, and kidney where its expression is induced by the presence of heme, hormones, metals, oxidative agents, and therapeutic compounds to protect against oxidative stress and inflammatory responses. HO-1 is upregulated in a variety of cancers and siRNA knockdown of HMOX1 or inhibition of HO-1 decreases cancer cell proliferation. HO-1 also interacts with the severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) accessory protein Orf3a that, in a similar virus, SARS-CoV, is associated with activation of the NLRP3 inflammasome. Cayman’s HO-1 protein can be used for ELISA and Western blot (WB) applications.
