It is a conjugated protein containing four haem groups and globin. There are two alpha and two beta chains (very similar to myoglobin) in adult humans, the haem moiety (an iron containing substituted porphyrin) is firmly held in a nonpolar crevice in each peptide chain.
there are four globin polypeptide chains, designated alpha, beta, gamma, delta in the adult. Each is composed of several hundred amino acids. A hemoprotein composed of globin and heme that gives red blood cells their characteristic color; function primarily to transport oxygen from the lungs to the body tissues; fish have simpler hemoglobin than mammals.