Studies on Soluble Cytochromes in Enterobacteriaceae

Purification of a hexaheme cytochrome C552 from Escherichia coli K 12 and its properties as a nitrite reductase

“…Cytochrome c552 is probably the inhibition site of cyanide and cupric ion in the system. Fujita and Sat0 found that cytochrome cs52 is located at the periplasmic space [8] and Jones et al observed nitrite reductase activity with viologen dyes as electron donor at the periplasmic side of the cytoplasmic membrane [26]. Considering the cellular location of cytochrome c 5 5 2 , electrons are probably not transferred from NADH to nitrite via soluble NADH oxidase, FAD, and cytochrome c552 [13].…”

“…In E. coli K12, this synthesis is under the control of an activator protein encoded by the j n r gene, which is necessary for the induced synthesis of a number of components in the anaerobic respiratory systems, including nitrate reductase, nitrite reductase, fumarate reductase, and hydrogenase [4] reported that reduced cytochrome c S s 2 from E. coli Yamaguchi is rapidly reoxidized by addition of nitrite. They found that cytochrome ~5 5 2 is located in the periplasinic space [8] and concluded that its in vivo function is reduction of toxic nitrite produced by nitrate respiration to ammonia at the cell surface 191. However, the protein-chemical properties of the cytochrome as a nitrite reductase have not been studied extensively.…”

Bacterial nitrite‐reducing enzymes

“…It contains 4-6 c haem molecules/SO-kDa subunit. Fujita (1966) and Sato (1966a, b, 1967) first identified a membrane-bound nitrite-reducing cytochrome c 5 s 2 in E. coli. The enzyme is part of an electron transfer chain for which formate has been shown to be the electron donor (Colc and Ward, 1973;Abou-Jaoude el al., 1979).…”

Energy conservation during the formate-dependent reduction of nitrite by Escherivhia coli

“…2). Reduction of nitrite is assumed to take place at the periplasmic surface of the membrane because this is the location of cytochrome c552 [15] which is possibly either the nitrite reductase itself or alternatively the immediate donor of electrons to the nitrite reductase. When an initial 2Fmol was supplemented by a further 2/~mol, steady-state BTPP + uptake occurred.…”