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