Cytoglobin, also known as CYGB, is a globin molecule ubiquitously expressed in all tissues and most notably utilized in marine mammals. Its avtual function is still unknown. It is thought to be a method of protection under conditions of hypoxia. The predicted function of cytoglobin is the transfer of oxygen from arterial blood to the brain. Cytoglobin is also present in chondroblasts and osteoblasts and shows a decreased level of expression upon differentiation to chondrocytes and osteocytes. Cytoglobin may facilitate diffusion of oxygen through tissues, scavenge nitric oxide or reactive oxygen species, or serve a protective function during oxidative stress.