文献类型：期刊文献

英文题名：Nitrogen metabolism of asparagine and glutamate in Vero cells studied by 1H/15N NMR spectroscopy

作者：Huang, Haiyan[1]; Yu, Yihua[2]; Yi, Xiaoping[1]; Zhang, Yuanxing[1]

机构：[1] State Key Laboratory of Bioreactor Engineering, East China University of Science and Technology, Shanghai 200237, China; [2] Shanghai Key Laboratory of Functional Magnetic Resonance Imaging, Department of Physics, East China Normal University, Shanghai 200062, China

年份：2007

卷号：77

期号：2

起止页码：427

外文期刊名：Applied Microbiology and Biotechnology

收录：EI(收录号：20074510907626)

语种：英文

外文关键词：Ammonia - Metabolism - Metabolites - Nitrogen - Nuclear magnetic resonance spectroscopy

摘要：Glutamine-free culture of Vero cells has previously been shown to cause higher cell yield and lower ammonia accumulation than that in glutamine-containing culture. Nitrogen metabolism of asparagine and glutamate as glutamine replacer was studied here using nuclear magnetic resonance (NMR) spectroscopy. 15N-labelled glutamate or asparagine was added and their incorporation into nitrogenous metabolites was monitored by heteronuclear multiple bond coherence (HMBC) NMR spectroscopy. In cells incubated with l-[15N]glutamate, the 15N label was subsequently found in a number of metabolites including alanine, aspartate, proline, and an unidentified compound. No detectable 15NH4+ signal occurred, indicating that glutamate was utilized by transamination rather than by oxidative deamination. In cells incubated with l-[2- 15N]asparagine, the 15N label was subsequently found in aspartate, the amine group of glutamate/glutamine, and in two unidentified compounds. Incubation of cells with l-[4-15N]asparagine showed that the amide nitrogen of asparagine was predominantly transferred to glutamine amide. There was no detectable production of 15NH4 +, showing that most of the asparagine amide was transaminated by asparagine synthetase rather than deaminated by asparaginase. Comparing with a glutamine-containing culture, the activities of phosphate-activated glutaminase (PAG), glutamate dehydrogenase (GDH) and alanine aminotransferase (ALT) decreased significantly and the activity of aspartate aminotransferase (AST) decreased slightly. ? 2007 Springer-Verlag.