Phycobiliproteins are water-soluble proteins present in cyanobacteria and certain algae (such as rhodophytes and cryptomonads), which play a crucial role in the light-harvesting process of photosynthesis. They are characterized by their vivid colors, ranging from blue to red, due to the presence of covalently attached bilin chromophores, which enable them to absorb light in regions of the spectrum not efficiently captured by chlorophyll.