During anaerobic nitrate respiration Bacillus subtilis reduces nitrate via nitrite to ammonia. No denitrification products were observed. B. subtilis wild-type cells and a nitrate reductase mutant grew anaerobically with nitrite as an electron acceptor. Oxygen-sensitive dissimilatory nitrite reductase activity was demonstrated in cell extracts prepared from both strains with benzyl viologen as ...

The 02-evolving complex (OEC) of photosynthesis resides near the inner side of the thylakoid membrane. Currently, it is believed to be composed of at least four polypeptides: (1) an intrinsic 27-34 kilodalton (kD) polypeptide that may be associated with manganese (Mn) ; (2) a peripheral 33 k D polypeptide, perhaps also associated with Mn; (3) a peripheral 24 kD polypeptide; and (4) a peripheral...

Using UV-visible spectrophotometric data of (1:1), electron donor-acceptor complexes (AD1, AD2 and AD3) have been investigated. The complexes concerned are n-butyl amine (D1) and cyclohexyl amine (D2) and phenyl hydrazine (D3) as electron donors with iron (III) ion as an electron acceptor (A) in methanol at 25°C. The values of formation constant (kAD), molar extinction coefficient (eAD), and ab...

Two thioacetyl-terminated ferrocene-anthraquinone donor-acceptor molecules with different pi-electron conjugative units have been synthesized via a series of Stille and Sonagashira reactions. Their photochemical and electrochemical properties before and after addition of an organic acid are investigated, indicating that these complexes are sensitive to external perturbation of protonation, lead...

Quinones feature prominently as electron acceptors in nature. Their electron-transfer reactions are often highly exergonic, for which Marcus theory predicts reduced electron-transfer rates because of a free-energy barrier that occurs in the inverted region. However, the electron-transfer kinetics that involve quinones can appear barrierless. Here, we consider the intrinsic properties of the par...

In highly purified plasma membrane fractions of at least six higher plant species, a specific high-potential b-type Cyt (redox potential at pH 7.0 between +120 and +160 mV, a band at 560-561 nm) has been detected (Asard et al., 1989; Askerlund et al., 1989). This component is reducible in vitro by sodium ascorbic acid and constitutes 60 to 80% of the total Cyt amount detectable in plant plasma ...

A donor–acceptor linked triad with a short spacer (Fc-ZnP-C60) 1 was designed and synthesised to attain the longest charge-separation lifetime, 630 ms, ever reported for triads at room temperature. The ferrocene electron donor and fullerene electron acceptor of triad 1 are attached to imidazole rings fused to opposite b,b0-pyrrolic positions of the zinc porphyrin. After excitation of the porphy...

The synthesis and characterization of a novel 2,5-diketopyrrolo[3,4-c]pyrrole(DPP)-based accepting building block with the scheme DPP-neutral small linker-DPP (Bi-DPP) is presented, which was utilized as electron accepting moiety for low band gap π-conjugated donor-acceptor copolymers as well as for a donor-acceptor small molecule. The electron accepting moiety Bi-DPP was prepared via a novel s...

The non-alternant aromatic azulene, an isomer of alternant naphthalene, differs from the latter in peculiar properties. large polarization ?-electron system over seven and five rings gives to azulene electrophile property a pronounced tendency donate electrons acceptor, substituted at 1 position. This paper presents cases which transfers suitable acceptor as methylium ions, positive charged het...