Reaction catalyzed by phycobiliprotein cysteine-84 phycobilin lyase (4.4.1.29)
[allophycocyanin alpha-subunit]-Cys84-phycocyanobilin
=
apo-[allophycocyanin alpha-subunit]
+
[allophycocyanin alpha-subunit]-Cys84-phycocyanobilin
=
apo-[allophycocyanin alpha-subunit]
+
(2R,3E)-phycocyanobilin