The component of hemoglobin responsible for binding oxygen, consists of an iron ion that binds oxygen and a porphyrin ring that binds the globin molecules; one molecule binds one molecule of oxygen
the Iron-holding part of the hemoglobin and myoglobin proteins (about 40% of the Fe in meat, fish and poultry is bound into heme) Hemoglobin: the oxygen-carrying protein of the red blood cells