Phycoerythrobilin synthase (EC 220.127.116.11, PebS) is an enzyme with systematic name (3Z)-phycoerythrobilin:ferredoxin oxidoreductase (from biliverdin IX alpha). This enzyme catalyses the following chemical reaction
(3Z)-phycoerythrobilin + 2 oxidized ferredoxin
biliverdin IX alpha + 2 reduced ferredoxin
This enzyme, from a cyanophage infecting oceanic cyanobacteria of the Prochlorococcus genus.