Immunochemistry of Biliproteins1

Siimmiary. BiliproteinS were extracted from representatives of the Cya nophiyta. Rhodophyta, and Crv,ptoplhvta and purified. Both purified and cru(le biliproteins were used to stinmulate rabbit antibody directed specifically against tlle biliproteins. The antigenic and immunogenic inter-relationships of these proteins were investigated bv the Ouclhterlony double diffusion technique. C-ph-cocyan'ins from all sources were foundl to be antigenically and immunogenically related and apparently also related to allophycocyanin but not to any of the phycoerythrins. Larger antigenic differences amilonig phyooervthrins from different grou,ps of algae were discovered. The ro'e of aggregation of the individual biliproteins in their immunochemistry was characterized. Attemiipts were made to determine the phylogenetic significance of these results. The immunochemical aspects of the billiproteins were striking in that {protein antigenls from vastly different cell types were found to be closely related. This relationship may be interpretedl as su,pporting the suiggestion that Rhodophyta evolved from Cyanophyta or fromii some common ancestral stock.