Chromoprotein: A conjugated protein, sulch as hemoglobin, that contains a pigmented prosthetic group, such as hem in hemoglobin (which makes blood red). Other examples of chromoprotein are: myoglobin, cytochromes and flavoproteins.

In hemoglobin:
chromoprotein (tetramer MW:4 x 16.125 =64.500)
Hem: Fe++ four pyrrol rings.