A blue carotenoprotein from the carapace of the crab, Carcinus maenas

Abstract

1. 1. A blue carotenoprotein ( λ max = 625 nm ) containing astaxanthin as prosthetic group was extracted and purified from the carapace of the crab, Carcinus maenas. 2. 2. The extraction was difficult to achieve, and the blue product was not always obtained. 3. 3. The blue carotenoprotein had an approximate mol. wt of 365,000 (gel filtration). Sodium dodecyl sulphate polyacrylamide gel electrophoresis indicated only a single polypeptide of 38,200 daltons, suggesting that the blue protein is an octameric form. 4. 4. In the presence of denaturing agents such as heat, organic solvents and SDS, the blue complex readily dissociated to liberate the orange carotenoid astaxanthin and a colourless apoprotein. No other lipid or sugar was detected.