R-PHYCOERYTHRIN FROM THE MACROALGA CORALLINA-OFFICINALIS (RHODOPHYCEAE) AND APPLICATION OF A DERIVED PHYCOFLUOR PROBE FOR DETECTING SUGAR-BINDING SITES ON CELL-MEMBRANES

R-Phycoerythrin (absorption spectrum 280; 495; sh 535, 564 nm with A564/A280 ratio of 5.3) was purified from the red macroalga Corallina officinalis. The relative molecular mass determined from PAGE was 240 000. SDS-PAGE demonstrated two major subunits of M(r) 20 000 and 21 000, respectively, and a minor subunit of M(r) 30000. A fucospyranosyl phenylisothiocyanate conjugate was prepared and this novel fluorescent affinity reagent used in conjunction with a flow cytometer to probe fucose-binding sites on blood mononuclear cells. By varying the sugar and using other phycobiliproteins the approach has the potential for simultaneously monitoring different sugar binding sites on subsets of cells within populations.