Electron donor for nitrite reductase from etiolated bean stems.

Nitrite, an electron donor for anoxygenic photosynthesis.

We report a previously unknown process in which anoxygenic phototrophic bacteria use nitrite as an electron donor for photosynthesis. We isolated a purple sulfur bacterium 98% identical to Thiocapsa species that stoichiometrically oxidizes nitrite to nitrate in the light. Growth and nitrate production strictly depended on both light and nitrite. This is the first known microbial mechanism for t...

Activation of Nitrite Reductase from Escherichia coli

Nitrite reductase from Escherichia coli K12 requires the presence of NAD+, one of the products of the reduction ofNO2by NADH, for full activity. The effect is observed with both crude extracts and purified enzyme. NAD+ also acts as a product inhibitor at high concentrations, and plots of initial rate against NAD+ concentration are bell-shaped. The maximum occurs at about 1 mM-NAD+, but increase...

Metabolites of 2,4-dichlorophenoxyacetic acid from bean stems.

Electron-spin-resonance studies of the NADH-dependent nitrite reductase from Escherichia coli K12.

The NADH-dependent nitrite reductase of Escherichia coli, which contains sirohaem, flavin, non-haem iron and labile sulphide, was examined by low-temperature e.s.r. spectroscopy. The enzyme, stored in the presence of nitrite and ascorbate, gave the spectrum of a nitrosyl derivative, with hyperfine splitting due to the nitrosyl nitrogen. On removal of these reagents, a series of signals centred ...

Evidence for Photoreduction of NADP + in a Suspension of Lysed Plastids from Etiolated Bean Leaves

N A D P H , N A D P + Photoreduction, Etioplasts, Absorbance Difference Spectra, Phaseolus vulgaris It has been investigated if photoreduction of N A D P + (detected by absorption spectroscopy) may take place in lysed plastids within minutes of exposure to light. This process was made possible by removal of oxidants from the reaction mixture. Lysed plastids were suspended in a medium containing...