Animal carotenoids—27. Further studies on the carotenoproteins crustacyanin and ovoverdin

Abstract

1. 1. The chirality of astaxanthin from the carotenoproteins of Homarus gammarus, crustacyanin (lobster shells) and ovoverdin (lobster eggs), has been examined by the camphanate method. Crustacyanin contained (3S,3′S)- axtaxanthin , (3R,3′S, meso)- astaxanthin and (3R,3′R)- astaxanthin in relative proportion 33:28:39. Astaxanthin ex ovoverdin consisted of the three optical isomers in ratio 30:28:42, closely similar to the ratio 31:25:44 found for total lobster egg astaxanthin. 2. 2. Individual recombination studies with apocrustacyanin and the natural astaxanthin mixture, the three pure, synthetic, optical isomers of astaxanthin and (3S)- adonirubin are reported. The recombined carotenoproteins were characterized by electronic and CD spectra and approximate mol. wt determined by ultrafiltration. 3. 3. The recombination method used resulted in carotenoproteins of α-crustacyanin size. The semisynthetic carotenoproteins obtained by recombination with each of the three astaxanthin isomers or (3S)- adonirubin showed only minor differences in their electronic and CD spectra relative to those of native α-crustacyanin. It is concluded that the chirality of the prosthetic group is not critical. 4. 4. No recombination between apo-ovoverdin and astaxanthin could be achieved. The CD properties for ovoverdin are discussed.