Anaerobic nucleotide reductases

Bilous PT, Cole ST, Anderson WF, Weiner JH. 1988. Nucleotide sequence of the dins ABC operon encoding the anaerobic dimethylsulfoxide reductase of Escherichia coli. Mol Microbiol 2 785-95. 

Promoter region of the nar operon, which encodes nitrate reductase in Escherichia coli. The promoter is generally only maximally induced under anaerobic conditions. It has been shown that the nar promoter in some strains of Escherichia coli can be induced under conditions of very low oxygen tension in the presence of nitrate. This observation has been used to develop some useful processes for recombinant protein expression in Escherichia coli. See Li, S.F. and DeMoss, J.A., Promoter region of the nar operon of Escherichia coli nucleotide sequence and transcription initiation signals, J. Bacteriol. 169, 4614- 620, 1987 Han, S.J., Chang,... 

The formation of succinate from fumarate by fumarate reductase (FR) and anaerobic phosphorylation of ADP to ATP are amongst the important reactions taking place in the mitochondria to provide energy to the helminths. The FR system of helminths differs from succinate dehydrogenase (SDH) of mammalian tissues in several ways. For example (a) FR requires NAD while SDH utilizes flavin nucleotide (FAD) as the coenzyme (b) FR acts only in one direction but SDH is a reversible enzyme (c) FR acts as the terminal electron acceptor under anaerobic conditions while SDH has no such property. Levamisole was shown to inhibit the FR in Ascaris [43]. 

A promising new area of enzymatic reactions is that of anaerobes. These organisms use redox systems that are not pyridine nucleotide dependent, but can use mcthylvirologen or benzylviologen (commercially available) as mediators. Electron donors can be hydrogen gas, formate, or carbon monoxide rather than glucose." The first new enzyme from this source is a 2-enoatc reductase, effected with stereospecific /rans-addition of hydrogen. An... 

When particulate preparations from bacteria grown anaerobically in the presence of nitrate are incubated with respiratory substrates or reduced pyridine nucleotides, it is observed that the cytochromes become reduced (Knook et ai, 1973 Lam and Nicholas, 1969 Ruiz-Herrera and DeMoss, 1969 Vila et al., 1977). Because the cytochrome b component is reoxidized when nitrate is added, it appears the Mo-protein (nitrate reductase) transfers electrons from cytochrome b to nitrate. These observations on dissimilatory nitrate reduction by bacteria are summarized in the following scheme. 

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