Characterization of a blue astaxanthin protein from the carapace of the crayfish Astacus leptodactylus

Abstract

1. 1. A blue carotenoprotein ( λ max = 634 nm) containing astaxanthin as prosthetic group, was extracted and purified from the carapace of the crayfish Astacus leptodactylus. 2. 2. The blue carotenoprotein contained (3 S,3′ S)-astaxanthin, (3 R,3′ S, meso)-astaxanthin and (3 R,3′ R)-astaxanthin in relative ratio 38:41:21. 3. 3. The blue carotenoprotein had an approximate mol. wt of 440,000 (gel filtration) and 437,000 (gradient gel electrophoresis). 4. 4. Sodium dodecyl sulphate polyacrylamide gel electrophoresis indicated the presence of two polypeptides of 19,600 and 18,600 daltons, with different mobility in polyacrylamide gel electrophoresis in the presence of 6 M urea. 5. 5. At low ionic strength and in the presence of denaturing agents such as SDS, urea, extreme pH and heat, the blue complex showed a greater stability than most of the carotenoproteins studied to date.