O2 and H2O are each the source of one O in NO− 2 produced from NH3 by Nitrosomonas: 15N‐NMR evidence

[摘要]

The exchange of ¹⁸O between H₂ ¹⁸O and exogeneously added ¹⁵N¹⁶O⁻ ₂ which occurs during oxidation of ammonia by Nitrosomonas is shown to occur one oxygen at a time. Conditions in which the exchange is diminished (notably the presence of ¹⁴NO^– ₂ and CCCP) allowed demonstration that water and dioxygen are each the source of one oxygen in nitrite produced from ¹⁵NH₃. The nitrate produced in the presence of ¹⁸O₂ consisted of 67 and 0% ¹⁵N¹⁸O¹⁶O⁻ and ¹⁵N¹⁸O¹⁸O⁻, respectively. Analysis was made using the ¹⁸O-isotope shift in ¹⁵N-NMR.

[学科分类] 生物化学/生物物理

[关键词] Nitrosomonas;15N-NMR;Nitrite;Ammonia;18O Isotope shift;Nitrification;CCCP;carbonyl cyanide m-chlorophenylhydrazone;PMS;N-methylphenazonium methosulfate