Heme oxygenase (HO) 

Heme oxygenase (HO) is an enzyme that catalyzes the degradation of heme to produce biliverdin/bilirubin, ferrous iron and carbon monoxide. Heme oxygenase (HO) can be divided into inducible type (HO-1) and constitutive type (HO-2). HO-1 is a kind of heat shock protein 32 (HSP32). Its expression level is low in normal physiological state, but it will increase significantly when induced by various stimuli such as oxidative stress, heavy metals, and inflammatory factors. HO-2 is continuously and stably expressed in brain, testis and other tissues, and is involved in maintaining the normal physiological function of cells. Heme oxygenase (HO) plays a key role in cell stress response and homeostasis, and the dysregulation of its expression or activity is related to the pathophysiology of cardiovascular disease, diabetes, obesity, lung disease, gastrointestinal disease, renal dysfunction, dermatitis, cancer and other diseases^[1].