Anaerobic ammonia oxidation by cell-free extracts of Nitrosomonas eutropha |
| |
Authors: | Ingo Schmidt Eberhard Bock |
| |
Institution: | (1) Institut für Allgemeine Botanik, Abteilung Mikrobiologie, Universität Hamburg, Ohnhorststraße 18, 22609 Hamburg, Germany |
| |
Abstract: | Cell-free extracts of Nitrosomonas eutropha oxidized ammonia to nitrite with NO2 (N2O4) as electron acceptor. The ammonia oxidation activity was shown to be sensitive against oxygen. In the absence of oxygen ammonia and NO2 were consumed in a ratio of approximately 1:2 and hydroxylamine occurred as an intermediate. NO was released in amounts equimolar to the consumption of NO2. After passing the cell suspension through a French pressure cell and fractionating it by density gradient centrifugation using a linear sucrose gradient, two soluble and two membrane fractions were detectable. Highest ammonia oxidation activity was measured in the membrane fractions and highest hydroxylamine oxidation activity in the soluble fractions. The KS values of the ammonia oxidizing system in cell-free extracts was about 20 m NH3 and remained unchanged between pH 7.25 to 8.25. |
| |
Keywords: | Nitrosomonas cell-free extracts anaerobic ammonia oxidation KS values nitrogen dioxide nitric oxide |
本文献已被 SpringerLink 等数据库收录! |