| Autor: |
Vries, Wytske, Niekus, H., Berchum, Hugerien, Stouthamer, A. |
| Zdroj: |
Archives of Microbiology; Mar1982, Vol. 131 Issue 2, p132-139, 8p |
| Abstrakt: |
Campylobacter sputorum subspecies bubulus contains a membrane-bound nitrite reductase which catalyses the six-electron reduction of nitrite to ammonia. Formate and L-lactate are used as hydrogen donors. Cells of C. sputorum grown with nitrate or nitrite contain cytochromes of the b-and c-type and a carbon monoxide-binding cytochrome c. In addition, a special membrane-bound carbon monoxide-binding pigment is found. Nitrite reduction with formate or L-lactate as a hydrogen donor is strongly inhibited by 2-n-heptyl-4-hydroxyquinoline-N-oxide (HQNO). Nitrite reduction by bacterial suspensions with lactate as a hydrogen donor is strongly inhibited by carbonylcyanide-m-chlorophenyl-hydrazone (CCCP) whereas nitrite reduction with formate as a hydrogen donor is not inhibited at all. →H/O values and →H/NO values were measured with ascorbate + N,N,N′,N′-tetramethyl-p-phenylenediamine (TMPD), formate (in the absence and presence of carbonic anhydrase) and L-lactate as a hydrogen donor. The results are summarized in a scheme for electron transport from formate or lactate to oxygen or nitrite which shows a periplasmic orientation of formate dehydrogenase and nitrite reductase and a cytoplasmic orientation of lactate dehydrogenase and oxygen reduction, and which shows proton translocation with a →H/2e value of 2.0. The →H/O and →H/NO values predicted by this scheme are in good agreement with the experimental values. [ABSTRACT FROM AUTHOR] |
| Databáze: |
Complementary Index |
| Externí odkaz: |
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