Another important member of the chromoprotein group of natural products is kedarcidin. Three classes of enediynes have since been identified&colon; calicheamicin, dynemicin, and chromoprotein based products. Phycoerythrocyanin is a kind of phycobiliprotein, magenta chromoprotein involved in photosynthesis of some Cyanobacteria. Chromoprotein enediynes are characterized by an unstable chromophore enediyne bound to an apoprotein. This chromoprotein consists of alpha- and beta-subunits, generally aggregated as hexamer. A chromoprotein is a conjugated protein that contains a pigmented prosthetic group (or cofactor). Neocarzinostatin (NCS) is a macromolecular chromoprotein enediyne antitumor antibiotic secreted by "Streptomyces macromomyceticus".