Chlorocruorin

Chlorocruorin is the respiratory pigment of some living marine annelids. It is present in dissolved form in their blood and is responsible for its yellow-green color. As in the hemoglobin oxygen on ferrous iron, which is associated with a porphyrin ring, is bound. The molar mass of about 2750 kDa.

Its structure it resembles the heme b. There is a vinyl group located at the 2 position of the porphyrin ring instead of the formyl group.