Choi B S, Roberts M F
Biochim Biophys Acta. 1987 May 18;928(3):259-65. doi: 10.1016/0167-4889(87)90184-4.
Methanobacterium thermoautotrophicum can utilize glutamine and urea as well as ammonia as the sole nitrogen source during growth on H2 and CO2. High-field 15N-NMR has been used to compare the assimilation of these different nitrogen sources by this organism. The 15N-NMR spectra of extracts of cells grown in media containing [delta-15N]glutamine as the nitrogen source show that the glutamine amide nitrogen is rapidly converted to glutamate. The 15N-NMR spectra of cell extracts from cells grown on [15N]urea show a marked increase in the labeling of the alpha-NH2 of glutamate concurrent with a decrease in the urea resonance. These two nitrogen sources do not show the metabolic shift to alanine as the major resonance in stationary phase as is seen with 15NH4Cl. This behavior is discussed in terms of the enzymes of nitrogen metabolism.
嗜热自养甲烷杆菌在以H2和CO2为生长底物时，能够利用谷氨酰胺、尿素以及氨作为唯一氮源。高场15N-NMR已被用于比较该生物体对这些不同氮源的同化作用。以[δ-15N]谷氨酰胺作为氮源在培养基中生长的细胞提取物的15N-NMR光谱表明，谷氨酰胺酰胺氮迅速转化为谷氨酸。以[15N]尿素为底物生长的细胞提取物的15N-NMR光谱显示，谷氨酸α-NH2的标记显著增加，同时尿素共振减少。与15NH4Cl不同，这两种氮源在稳定期不会出现代谢转变为丙氨酸作为主要共振峰的情况。本文根据氮代谢酶对这种行为进行了讨论。
