IUBMB Enzyme Nomenclature


Accepted name: phycobiliprotein cysteine-84 phycobilin lyase

Reaction: (1) [C-phycocyanin β-subunit]-Cys84-phycocyanobilin = apo-[C-phycocyanin β-subunit] + (2R,3E)-phycocyanobilin
(2) [phycoerythrocyanin β-subunit]-Cys84-phycocyanobilin = apo-[phycoerythrocyanin β-subunit] + (2R,3E)-phycocyanobilin
(3) [allophycocyanin α-subunit]-Cys84-phycocyanobilin = apo-[allophycocyanin α-subunit] + (2R,3E)-phycocyanobilin
(4) [allophycocyanin β-subunit]-Cys84-phycocyanobilin = apo-[allophycocyanin β-subunit] + (2R,3E)-phycocyanobilin
(5) [C-phycoerythrin α-subunit]-Cys84-phycoerythrobilin = apo-[C-phycoerythrin α-subunit] + (2R,3E)-phycoerythrobilin
(6) [C-phycoerythrin β-subunit]-Cys84-phycoerythrobilin = apo-[C-phycoerythrin β-subunit] + (2R,3E)-phycoerythrobilin

Glossary: phycocyanobilin = 3,31-didehydro-2,3-dihydromesobiliverdin
phycoerythrobilin = 3,31,181,182-tetradehydro-2,3,15,16-tetrahydromesobiliverdin

Other name(s): cpcS (gene name); cpeS (gene name); cpcS1 (gene name); cpcU (gene name); phycocyanobilin:Cys-β84-phycobiliprotein lyase

Systematic name: [phycobiliprotein]-Cys84-phycobilin:phycobilin lyase

Comments: The enzyme, found in cyanobacteria and red algae, catalyses the attachment of phycobilin chromophores to cysteine 84 of several phycobiliproteins (the numbering used here corresponds to the enzyme from Anabaena, in other organisms the number may vary slightly). It can attach phycocyanobilin to the β subunits of C-phycocyanin and phycoerythrocyanin and to both subunits of allophycocyanin. In addition, it can attach phycoerythrobilin to both subunits of C-phycoerythrin.

Links to other databases: BRENDA, EXPASY, KEGG, MetaCyc, CAS registry number:


1. Zhao, K.H., Su, P., Li, J., Tu, J.M., Zhou, M., Bubenzer, C. and Scheer, H. Chromophore attachment to phycobiliprotein β-subunits: phycocyanobilin:cysteine-β84 phycobiliprotein lyase activity of CpeS-like protein from Anabaena Sp. PCC7120. J. Biol. Chem. 281 (2006) 8573-8581. [PMID: 16452471]

2. Zhao, K.H., Su, P., Tu, J.M., Wang, X., Liu, H., Ploscher, M., Eichacker, L., Yang, B., Zhou, M. and Scheer, H. Phycobilin:cystein-84 biliprotein lyase, a near-universal lyase for cysteine-84-binding sites in cyanobacterial phycobiliproteins. Proc. Natl. Acad. Sci. USA 104 (2007) 14300-14305. [PMID: 17726096]

3. Saunee, N.A., Williams, S.R., Bryant, D.A. and Schluchter, W.M. Biogenesis of phycobiliproteins: II. CpcS-I and CpcU comprise the heterodimeric bilin lyase that attaches phycocyanobilin to Cys-82 of β-phycocyanin and Cys-81 of allophycocyanin subunits in Synechococcus sp. PCC 7002. J. Biol. Chem. 283 (2008) 7513-7522. [PMID: 18199753]

4. Kupka, M., Zhang, J., Fu, W.L., Tu, J.M., Bohm, S., Su, P., Chen, Y., Zhou, M., Scheer, H. and Zhao, K.H. Catalytic mechanism of S-type phycobiliprotein lyase: chaperone-like action and functional amino acid residues. J. Biol. Chem. 284 (2009) 36405-36414. [PMID: 19864423]

[EC created 2015]

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