Phycoerythrin

R-Phycoerythrin (R-PE) is an orange fluorescent protein with absorption wavelength that peaks around 565 nm, and an emission maximum at around 575-578 nm. When conjugated to proteins- particularly antibodies, phycoerythrin enables antigen detection for applications such as flow cytometry. While it emits bright fluorescence, phycoerythrin photobleaches rather quickly, limiting its use in fluorescence microscopy.