hemerythrin

biochemistry

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June 29, 2026

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Hemerythrin is an iron-containing respiratory pigment found in the blood of certain marine invertebrates, such as some brachiopods. Unlike hemoglobin, hemerythrin does not contain porphyrin groups. Instead, it has three times as much iron, which is directly attached to the protein. These pigments are violet in color and play a crucial role in oxygen transport within these animals. Hemerythrin is one of several types of respiratory pigments found in invertebrates, each with unique structures and properties for carrying oxygen.12

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coloration
Hemerythins
Iron-containing, proteinaceous pigments, hemerythrins are present in the blood of certain bottom-dwelling marine worms (notably burrowing sipunculids) and of the brachiopod Lingula; the pigments serve as oxygen-carriers.
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Iron-containing, proteinaceous pigments, hemerythrins are present in the blood of certain bottom-dwelling marine worms (notably burrowing sipunculids) and of the brachiopod Lingula; the pigments serve as oxygen-carriers.
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circulatory system
Blood
The third iron-containing pigments, the hemerythrins, are violet. They differ structurally from both hemoglobin and chlorocruorin in having no porphyrin groups and containing three times as much iron, which is attached directly to the protein. Hemerythrins are restricted to a small number of animals, including some polychaete and sipunculid worms,…
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The third iron-containing pigments, the hemerythrins, are violet. They differ structurally from both hemoglobin and chlorocruorin in having no porphyrin groups and containing three times as much iron, which is attached directly to the protein. Hemerythrins are restricted to a small number of animals, including some polychaete and sipunculid worms,…
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