Biology:Coboglobin

A coboglobin is a synthetic compound, a metalloprotein chemically similar to hemoglobin or myoglobin but using the metal cobalt instead of iron (hence the name). Just like hemoglobin and myoglobin, the coboglobins are able to reversibly bind molecular oxygen (O₂) at the metal atom. However, they lose this ability much faster than the natural molecules. Blood of this type would be uncoloured and clear when in the veins while amber yellow in colour in the arteries.

References

• Hoffman, B. M.; Petering, D. H (October 1970). "Coboglobins: Oxygen-Carrying Cobalt-Reconstituted Hemoglobin and Myoglobin.". Proceedings of the National Academy of Sciences 67 (2): 637–643. doi:10.1073/pnas.67.2.637. PMID 4331717. 
• Marden, Michael C. (28 April 2000). "Modulation of the Oxygen Affinity of Cobalt-Porphyrin by Globin". FEBS Letters 472 (2–3): 221–224. doi:10.1016/S0014-5793(00)01423-X. PMID 10788615. .