Further characterization of the orange carotenoid protein extracted from the marine demosponge Axinella verrucosa

The orange coloration of the marine sponge A. verrucosa is provided by some carotenoids widespread in the ectosome and mesohyl of this sponge. These carotenoids are bound to a glyco(lipo)protein forming a non covalent complex. Six carotenoids are bound to the glyco(lipo)protein, but only alpha-carotene was identified by HPLC. The aminoacid composition is quite different from those previously reported in Porifera. The content of Ser and Gly and the total polar residues are high. The presence of Met and Pro was not evidenced. Some unusual aminoacids were detected, of which only Taurine was probably identified.