Abstract
We investigated the subunit structures of the three agglutinins (BRA-1, BRA-2, and BRA-3) isolated from the coelomic fluid of the acorn barnacle, Megabalanus rosa, by high-speed gel filtration, gel electrophoresis, CD spectra, and peptide mapping. BRA-2 (Mr 140, 000) and BRA-3 (Mr 64, 000) were glycoproteins composed of subunits having two identical basic units cross-linked by disulfide bonds. The basic units of BRA-2 and BRA-3 had molecular weights of 22, 000 and 18, 000, respectively. They did not have a common structure. BRA-1 (Mr 330, 000) was composed of subunits homologous to that of BRA-2. The binding properties of these agglutinins against rabbit erythrocyte ghosts were also investigated after labeling the agglutinins with fluorescein isothiocyanate.
