PURIFICATION AND PROPERTIES OF PHYCOBILIPROTEIN OF SPIRULINA SUBSALSA VAR.

Two types of phycobiliproteins, C-PC and APC, were separated just after crude phycobiliproteins from S. subsalsa var. were precipitated in 50% (NH4)SO4 and then loaded on a 1×4cm hydroxylapatite column.The C-PC with a purity of 7.27 (A 620/A 280) possesses absorption maximum at 620 nm and a room fluorescence emission at 642 nm, while the APC with a purity of 6.55 (A 650/A 280) have an absorption maximum at 650 nm and a room fluorescence emission at 657 nm.When the purified C-PC and APC were electrophoresed under non-denaturing PAGE condition, only one band was observed (data not shown). Under denaturation (by means of 11.5% SDS-polyacrylamide slab gels or 7—15% SDS polyacrylamide slab gels), C-PC yielded two coloured polypeptides with the molecular weights of 16.0 and 19.5 kD for its α and β subunits, respectively; whereas APC comprised two slightly coloured polypeptides of molecular weights of 15.5 and 18.0 kD for its α and β subunits, respectively. Sometimes APC had a colorless polypeptide band with a molecular weight of 14.0 kD which was probably a core component of phycobilisome as discussed by Glazer in 1985 for Synechocystis 6701. According to these data, the minimum molecular weights (C-PC, 35,500; APC, 33,500) of phycobiliproteins from S. subsalsa var. are smaller than those from S. plantensis. The amino acid composition and isoelectric points of C-PC and APC were also determined.The total content of phycobiliproteins was estimated at 28.4% of dry weight of S. subsalsa var. Thus it is higher than that of other blue-green algae.The above results show that Spirulina subsalsa var. is an ideal source for edible protein.