Oxyhemoglobin
The oxygen-loaded form of hemoglobin, the predominant protein in red blood cells.
Hemoglobin is a protein molecule that binds to oxygen.
Hemoglobin forms an unstable, reversible bond with oxygen.
In its oxygen-loaded form, it is called oxyhemoglobin and is bright red.
In the oxygen-unloaded form it is called deoxyhemoglobin and is purple-blue.