What is "phycoerythrin"

Phycoerythrin \Phy`co*e*ryth"rin\, Phycoerythrine \Phy`co*e*ryth"rine\, n. [Gr. ? seaweed + E. erythrin, -ine.] A red coloring matter found in alg[ae] of the subclass Floride[ae].

n. (context protein English) A red, light-harvesting protein found in cyanobacterium, red algae and cryptomonads

n. red pigment in red algae

Phycoerythrin (PE) is a red protein- pigment complex from the light-harvesting phycobiliprotein family, present in red algae and cryptophytes, accessory to the main chlorophyll pigments responsible for photosynthesis.

Like all phycobiliproteins, it is composed of a protein part covalently binding chromophores called phycobilins. In the phycoerythrin family, the most known phycobilins are: phycoerythrobilin, the typical phycoerythrin acceptor chromophore, and sometimes phycourobilin. Phycoerythrins are composed of (αβ) monomers, usually organised in a disk-shaped trimer (αβ) or hexamer (αβ) (second one is the functional unit of the antenna rods). These typical complexes contain also third type of subunit, the γ chain.

The phycobiliproteins that bind the highest number of phycobilins (up to ten per αβ monomer). (this non sequitur needs to be corrected)