Heme oxygenase-1 (HO-1)

Heme oxygenase-1 (HO-1) is an inducible enzyme that catalyzes the first and rate-limiting step in the oxidative degradation of heme, producing biliverdin, ferrous iron (Fe²⁺), and carbon monoxide (CO). It plays a crucial role in cellular defense mechanisms, particularly under conditions of stress such as inflammation, hypoxia, or exposure to toxins. HO-1 serves several protective functions including antioxidant defense, anti-inflammatory effects, and cytoprotection.

Induction of HO-1 leads to cytoprotective effects by degrading heme and producing biliverdin, ferrous iron, and carbon monoxide, which modulate inflammation and oxidative stress.