Crustacyanin is a carotenoprotein

biological pigment A biological pigment, also known simply as a pigment or biochrome, is a substance produced by living organisms that have a color resulting from selective Absorption (electromagnetic radiation), color absorption. Biological pigments include plant ...

found in the

exoskeleton An exoskeleton () . is a skeleton that is on the exterior of an animal in the form of hardened integument, which both supports the body's shape and protects the internal organs, in contrast to an internal endoskeleton (e.g. human skeleton, that ...

lobster Lobsters are Malacostraca, malacostracans Decapoda, decapod crustaceans of the family (biology), family Nephropidae or its Synonym (taxonomy), synonym Homaridae. They have long bodies with muscular tails and live in crevices or burrows on th ...

s and

blue crab Blue crab may refer to: * Blue Crab 11, an American sailboat design * ''Callinectes sapidus ''Callinectes sapidus'' (from the Ancient Greek language, Ancient Greek ,"beautiful" + , "swimmer", and Latin , "savory"), the blue crab, Atlantic blue ...

s and responsible for their blue colour. β-Crustacyanin (β-CR), is composed of two stacked

astaxanthin Astaxanthin is a keto- carotenoid within a group of chemical compounds known as carotenoids or terpenes. Astaxanthin is a metabolite of zeaxanthin and canthaxanthin, containing both hydroxyl and ketone functional groups. It is a lipid-solu ...

carotenoids that absorb at λ = 580–590 nm (2.10–2.14 eV). α-crustacyanin (α-CR) is an assembly of eight β-CR

protein dimer In biochemistry, a protein dimer is a macromolecular complex or protein multimer, multimer formed by two protein monomers, or single proteins, which are usually Non-covalent interaction, non-covalently bound. Many macromolecules, such as proteins ...

s. It is a 320 kDa (

atomic mass Atomic mass ( or ) is the mass of a single atom. The atomic mass mostly comes from the combined mass of the protons and neutrons in the nucleus, with minor contributions from the electrons and nuclear binding energy. The atomic mass of atoms, ...

) complex containing 16 astaxanthin molecules. Although the β-CR dimer has a peak wavelength of 580 nm, α-CR exhibits a bathochromic shift to 632 nm; the mechanism and function of the additional wavelength shift is not understood.

References

{{reflist Biological pigments