Effect of Ferredoxin on the Diaphorase Activity of Cyanobacterial Ferredoxin-NADP Reductase.
نویسندگان
چکیده
The interaction of ferredoxin-NADP reductase (FNR) and ferredoxin (Fd) results in an enhanced rate of reaction and a shift of the pH optimum for the FNR-mediated diaphorase reaction. Low concentrations of NaCl (<100 millimolar), favorable for formation of the FNR:Fd complex, further magnify the alteration of the diaphorase reaction; the activity is enhanced 3-fold and pH optimum is shifted from 9.5 to 7.8. The Fd-stimulated diaphorase activity of FNR may result either from a conformational change of the enzyme and/or from a transition from a two electron to a one electron reaction.
منابع مشابه
Interaction between ferredoxin and ferredoxin nicotinamide adenine dinucleotide phosphate reductase in pyridine nucleotide photoreduction and some partial reactions. I. Inhibition of ferredoxin nicotinamide adenine dinucleotide phosphate reductase by ferredoxin.
Purified ferredoxin has been shown to inhibit reactions mediated by the flavoprotein ferredoxin-NADP reductase. Ferredoxin inhibits the transfer of electrons from NADPH to ferricyanide (diaphorase activity) to NAD (transhydrogenase) and the photoreduction of pyridine nucleotides during the Hill reaction. On the basis of the kinetics of inhibition, it is suggested that the flavoprotein has two b...
متن کاملLocalization and Quantitative Determination of Ferredoxin-NADP Oxidoreductase, a Thylakoid-Bound Enzyme in the Cyanobacterium Anabaena sp. Strain 7119.
Thylakoid membrane preparations obtained from mechanically disrupted (sonicated) cells of the cyanobacterium Anabaena sp. strain 7119 show a membrane-bound ferredoxin-NADP(+) oxidoreductase (EC 1.18.1.2) as determined either by specific antibodies or by using the ferredoxin-dependent NADPH-cytochrome c reductase activity, which is a specific test for this enzyme. However, in contrast with highe...
متن کاملInteraction of Ferredoxin-NADP Oxidoreductase with the Thylakoid Membrane.
The binding of ferredoxin-NADP reductase to spinach chloroplast membranes was studied by washing the membranes with different media. Release of the enzyme from the thylakoids was greater in 0.75 millimolar EDTA but was not complete inasmuch as 20% the activity remained membrane-bound after three washes.A Scatchard plot of binding experiments suggests the presence of one type of binding site and...
متن کاملRole of the C-terminal extension stacked on the re-face of the isoalloxazine ring moiety of the flavin adenine dinucleotide prosthetic group in ferredoxin-NADP(+) oxidoreductase from Bacillus subtilis.
Ferredoxin-NADP(+) oxidoreductase [EC 1.18.1.2] from Bacillus subtilis (BsFNR) is homologous to the bacterial NADPH-thioredoxin reductase, but possesses a unique C-terminal extension that covers the re-face of the isoalloxazine ring moiety of the flavin adenine dinucleotide (FAD) prosthetic group. In this report, we utilize BsFNR mutants depleted of their C-terminal residues to examine the impo...
متن کاملAn in vivo system involving co-expression of cyanobacterial flavodoxin and ferredoxin–NADP+ reductase confers increased tolerance to oxidative stress in plants
Oxidative stress in plants causes ferredoxin down-regulation and NADP(+) shortage, over-reduction of the photosynthetic electron transport chain, electron leakage to oxygen and generation of reactive oxygen species (ROS). Expression of cyanobacterial flavodoxin in tobacco chloroplasts compensates for ferredoxin decline and restores electron delivery to productive routes, resulting in enhanced s...
متن کاملذخیره در منابع من
با ذخیره ی این منبع در منابع من، دسترسی به آن را برای استفاده های بعدی آسان تر کنید
برای دانلود متن کامل این مقاله و بیش از 32 میلیون مقاله دیگر ابتدا ثبت نام کنید
ثبت ناماگر عضو سایت هستید لطفا وارد حساب کاربری خود شوید
ورودعنوان ژورنال:
- Plant physiology
دوره 77 1 شماره
صفحات -
تاریخ انتشار 1985