An Immunological Approach to Ferredoxin Specificity and Activity

1. Antibodies to Swiss‐Chard ferredoxin were prepared and were shown to interact with plant ferredoxin and blue green algal ferredoxin, but not with clostridial ferredoxin. 2. Ferredoxin‐dependent electron transport and photophosphorylation reactions were markedly inhibited by the antibodies, but N‐methylphenazonium‐methosulfate‐mediated phosphorylation was not. 3. The antibody preparation inhibited endogenous cyclic and pseudocyclic photophosphorylations, in the absence of added ferredoxin.