phycobilin
Phycobilins are a class of water-soluble pigment molecules found in cyanobacteria and some algae. They function as chromophores that are covalently bound to protein subunits to form phycobiliproteins, which assemble into large light-harvesting complexes called phycobilisomes that associate with photosynthetic membranes.
The main phycobiliproteins are phycocyanin, phycoerythrin, and allophycocyanin. Each contains specific bilin chromophores: phycocyanin carries phycocyanobilin,
Phycobilins broaden the range of light absorption by capturing wavelengths that chlorophylls absorb less efficiently, particularly
Biosynthesis involves bilin chromophores derived from biliverdin, produced via heme degradation, followed by enzymatic modification to
Ecologically, phycobiliproteins are characteristic of cyanobacteria and red algae, where they support light harvesting in chloroplast-containing
In addition to their biological role, phycobiliproteins have notable applications as natural colorants and fluorescent labels,