HMOX1 dimer, HMOX2 cleave heme

Heme oxygenases (HMOXs) cleaves the heme ring at the alpha-methene bridge to form bilverdin. This reaction forms the only endogenous source of carbon monoxide. HMOX1 is inducible and is thought to have an antioxidant role as it is activated in virtually all cell types and by many types of "oxidative stress" (Poss & Tonegawa 1997). HMOX1 forms dimers/oligomers in the endoplasmatic reticulum. This oligomerization is crucial for the stabilization and function of HMOX1 in the ER (Hwang et al. 2009). HMOX2 is non-inducible.

血红素加氧酶（HMOXs）通过裂解血红素环上的α-亚甲基桥形成胆绿素。此反应构成了碳单氧化物唯一的内源性来源。HMOX1具有可诱导性，并被认为具有抗氧化作用，因为它几乎在所有细胞类型和多种类型的“氧化应激”中被激活（Poss & Tonegawa 1997）。HMOX1在内质网中形成二聚体/寡聚体。这种寡聚化对于HMOX1在内质网中的稳定性和功能至关重要（Hwang et al. 2009）。HMOX2不具有可诱导性。