Phycoerythrin

phycoerythrin [¦fī·kō·ə′rith·rən]

(biochemistry)

A red phycobilin.

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Phycoerythrin 

the name for any of the red pigments of the phycobilin group found in red and blue-green algae. The three forms of phycoerythrins are R, B, and C, which are differentiated by spectral characteristics and designated without relation to the origin of the pigments. The molecular weight ranges from 72,000 to 300,000. The protein part is composed of globular proteins, associations of several subunits that are covalently bonded to two to four phycoerythrobilins. Isolated chromophore groups have identical spectral and chemical properties in all phycoerythrins, but the absorption spectra of various phycoerythrins differ in the position and intensity of bands in the region of 500–570 nanometers (nm). All phycoerythrins have a fluorescence maximum of 575–585 nm.

Phycoerythrins transfer the energy they absorb from sunlight to photochemically active chlorophyll a.