CHARACTERIZATION OF PHYCOBILIPROTEINS PRESENT IN GRACILARIA-CHILENSIS

This report involves the extraction, the purification and a general ch aracterization of the phycobiliproteins present in the red algae Graci laria chilensis (Bird, McLachlan y Oliveira). Three phycobiliproteins were purified, R-phycoerythrin (PE) (lambda(max) = 566 nm, 540 nm); ph ycocyanin (PC) (lambda(max) = 621 nm and 550 nm); and allophycocyanin (APC) (lambda(max) = 651 nm and a shoulder at 620 nm). The alpha and b eta structura subunits of each protein, have molecular weights 18 kD, 16 kD and 15 kD, respectively. A spectroscopic method to determine the amount of each type of phycobiliprotein in a mixture is proposed. Thi s method was used to make a comparison among the phycobiliprotein comp osition in phycobilisomes isolated from pigmentation variants of the s ame specie (green, dark green and brown reddish). The molar ratio, APC : PC : PE was 10 : 4 : 2 for green variant, 10 : 3 : 6 for the dark gr een variant and 10 : 2 : 10 for the brown reddish variant.