One-step purification of R-phycoerythrin from the red edible seaweed Grateloupia turuturu

•A chromatography method to purify R-phycoerythrin of Grateloupia turuturu is optimized.•Native R-phycoerythrin is obtained with a purity index of 2.89 and a recovery yield of 27%.•We report two forms of R-phycoerythrins: native form at approx. 260 kDa and dissociated form at approx. 60 kDa.

A one-step chromatographic method for the purification of R-phycoerythrin (R-PE) of Grateloupia turuturu Yamada is described. Native R-PE was obtained with a purity index of 2.89 and a recovery yield of 27% using DEAE-Sepharose Fast Flow chromatography with a three-step increase in ionic strength. The analysis by SDS electrophoresis showed a broad band between 18 and 21 kDa in size corresponding to subunits α and β and a low intensity band of 29 kDa corresponding to the γ subunit. Two forms of R-PE were identified by gel filtration chromatography: a native form with a molecular weight of 260 ± 5 kDa and a dissociated form with a molecular weight of 60 ± 2 kDa. The native form presented the characteristic absorption spectrum of R-PE with three absorbance maxima at 498, 540 and 565 nm, whereas the dissociated form presented only the 498 and 540 nm peaks. Moreover, the two forms displayed two different fluorescence maxima.