Phycocyanin, phycoerythrin and allo-phycocyanin are collectively called phycobilins. Seven types of phycobilins are found. Cyanobacteria and red algae contain phycobilins. Phycobilins store light energy and help in photosynthesis. The red colored phycobilin is called phycoerythrin. It absorbs blue-green light. Its chemical symbol is C34H46O8N4. The blue colored phycobilin is called phycocyanin. It absorbs orange light. Its chemical symbol is C34H46O8N4.