The phycobilin pigments were freshly extracted from Porphyra naiadum in the cold.
At least two types of phycoerythrin (I and II) can be distinguished by electrophoresis, chromatography, and spectral characteristics.
At pH 5.0 phycoerythrin II has a relatively large negative charge, while phycoerythrin I is nearly iso-electric. At pH 7.0, however, phycoerythrin I has the larger negative charge. Mobilities have been calculated by visual measurement of electrophoresis.
Phycoerythrin II can be converted to phycoerythrin I by storing at pH 7.0.
Chromatography indicates at least two types of phycocyanin as well.