Quantitative Determination of Ferredoxin, Ferredoxin-NADP+ Reductase and Plastocyanin in Spinach Chloroplasts

Ferredoxin, ferredoxin-NADP+ reductase and plastocyanin extracted from spinach chloroplasts were determined by quantitative immunoelectrophoresis in an antiserum-containing gel. The advantage of the method is its high sensitivity and specificity so that crude extracts can be directly analysed. It requires, however, purified electron carriers and the corresponding monospecific antibodies. The ratios of ferredoxin to reductase to plastocyanin approximated 5:3:4, respectively, per cytochrome f or P700 in spinach chloroplasts.