Purification and characterization of biliverdin-binding protein from larval hemolymph of the swallowtail butterfly, Papilio xuthus L.

The biliverdin-binding protein from the larval hemolymph of the swallowtail butterfly, Papilio xuthus L., was purified and characterized. The crude bi liverdin-binding protein, obtained by ammonium sulfate fractionation, was p urified in two steps, the first one by gel filtration chromatography and th e second one by ion-exchange chromatography. The molecular mass of the puri fied protein was analyzed by SDS-polyacrylamide gel electrophoresis and est imated to be 21 kDa. The N-amino terminal sequence of P. xuthus biliverdin- binding protein analyzed up to the 19th residue showed that 42% of the amin o acid sequence are sequence similarity to the bilin-binding protein from P ieris brassicae. These results suggest that the P. xuthus biliverdin-bindin g protein belongs to the insecticyanin-type.