Different preparative procedures for isolation and purification of plastocyanin were successful to obtain the pure protein from Chlorella vulgaris, Scenedesm us acutus and Spinacia oleracea but not from B um illeriopsis filiform is. Lade of plastocyanin in this alga was further confirmed by the following in comparison with spinach chloroplast material:
a. Use of antibodies to block photosynthetic reactions generally dependent on plastocyanin;
b. epr spectral assessment;
c. treatment of chloroplasts with KCN and amphotericin B ;
d. light-induced changes at 553 nm ( = cytochrome f photooxidation).
The latter assays indicated that, in contrast to spinach, neither plastocyanin nor cytochrome f ( = Cyt 553) is present in sonified or pyridine treated Bumilleriopsis chloroplasts. Photooxidation of (added) cytochrome 553 takes place not only without plastocyanin but is counteracted by the copper protein