title: Trinitrophenylation of spinach ferredoxin and its effect on the functions.
abstract: Spinach ferredoxin was trinitrophenylated by reaction with 2,4,6-trinitrobenzenesulfonate. Four amino groups in the ferredoxin could be modified of the total of five amino groups. The trinitrophenylated ferredoxin formed a complex with ferredoxin-NADP+ reductase just as native ferredoxin did. The modified ferredoxin also retained the activity of electron transport in the cytochrome c photoreduction system of chloroplasts, but could neither donate electrons to ferredoxin-NADP+ reductase in the NADP+ photoreduction system, nor accept electrons from the reductase in the NADPH-cytochrome c reduction system in vitro. Furthermore, it lost the inhibitory effect against the NADPH-diaphorase activity of the reductase. These results suggest that the complex formation of ferredoxin with ferredoxin-NADP+ reductase is a phenomenon essentially independent of the function of electron transport between the two proteins.
mesh_terms: D002736:Chloroplasts / Q000378:metabolism*; D004579:Electron Transport; D005288:Ferredoxins / Q000378:metabolism*; D009245:NADH Dehydrogenase / Q000378:metabolism; D009252:NADPH Dehydrogenase / Q000378:metabolism; D010944:Plants; D013057:Spectrum Analysis; D013329:Structure-Activity Relationship; D014301:Trinitrobenzenes
chemical_list: D005288:Ferredoxins; D014301:Trinitrobenzenes; D009252:NADPH Dehydrogenase; D009245:NADH Dehydrogenase