A phycoerythrin-allophycocyanin (PE-AP) complex was obtained from intact phycobilisomes of the marine red alga Polysiphonia urceolata. Study of spectral properties and polypeptide components showed that the complex contains PE, phycocyanin, AP, and higher proportional linker proteins of the four groups present in intact phycobilisomes. and Li Sun, Shumei Wang.