Phycobilins - Phycobilins are water soluble open chain tetrapyrroles which are present in red algae and blue green bacteria (Cyanobacteria).
There are two kinds of phycobilins, phycocyanins and phycoerythrins.Phycocyanins are predominate in the blue green bacteria, while phycoerythrins predominate in the red algae. Phycobilins are mainly present in PSII, but are also present in PS I.
