A vertebrate globin expressed in the brain

Haemoglobins and myoglobins constitute related protein families that function in oxygen transport and storage in humans and other vertebrates(1,2). Here we report the identification of a third globin type in man and mouse. This protein is predominantly expressed in the brain, and therefore we have called it neuroglobin. Mouse neuroglobin is a monomer with a high oxygen affinity (half saturation pressure, P(50) approximate to 2 torr). Analogous to myoglobin, neuroglobin may increase the availability of oxygen to brain tissue. The human neuroglobin gene (NGB), located on chromosome 14q24, has a unique exon-intron structure. Neuroglobin represents a distinct protein family that diverged early in metazoan evolution, probably before the Protostomia/Deuterostomia split.