Red Fluorescent Protein - R-PE (R-Phycoerythrin)

R-phycoerythrin (R-PE) is an intensely bright phycobiliprotein isolated from red algae that exhibits extremely bright red-orange fluorescence with high quantum yields. The broad excitation spectrum provides the advantage for multi-color immunofluorescent staining or cell sorting. R-PE consists of a, b and g subunits and is present as (ab) 6g. R-PE and the closely related BPE are the most intensely fluorescent phycobiliproteins having orange fluorescence. R-PE is a large molecule used for fluorescence-based detection, primarily in flow cytometry, microarray assays, ELISAs, and other applications that require high sensitivity but not photostability. In practical applications, the sensitivity of R-PE conjugates is usually 5 to 10 times greater than those of the corresponding fluorescein conjugates.