Phycoerythrin

Phycoerythrin is in Cyanobacteria ( blue-green algae ) and red algae occurring red accessory pigment in photosynthesis. It consists of a protein complex, which carries a chromophore group as the central atom coordinates the copper. Phycoerythrin is grouped with the phycocyanin to the phycobiliproteins. Its absorption spectrum shows absorption maxima at wavelengths of 496 nm, 529 to 534 nm and 555 nm phycobilins absorb photons of wavelengths which does not have chlorophyll absorption. Phycoerythrin directs the energy via the detour of phycocyanin to chlorophyll on. The quantum efficiency of phycobilins is even higher than that of chlorophyll.

In Rhodomonas the complex consists of a tetramer of two of four different α - β units and 2 identical units.

Algae that hold this pigment (eg Planktothrix rubescens ), can use the weak light in the depth of water where the chlorophyll left over green light only is available in appreciable intensities.

Certain forms of phycoerythrin can be used in the biological and biomedical research in various laboratory methods as a fluorescent dye. These methods include, for example, flow cytometry and immunofluorescence.