label: apo-L-cysteinyl(84)-[R-phycocyanin alpha-subunit] + (2R,3E)-phycoerythrobilin => phycourobilin-L-cysteinyl(84)-[R-phycocyanin alpha-subunit]
label_lc: apo-l-cysteinyl(84)-[r-phycocyanin alpha-subunit] + (2r,3e)-phycoerythrobilin => phycourobilin-l-cysteinyl(84)-[r-phycocyanin alpha-subunit]