Application of gas chromatography-mass spectrometry to in vitro studies of nitrogen metabolism.
Application of gas chromatography-mass spectrometry to in vitro studies of nitrogen metabolism.
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气相色谱-质谱联用法在体外氮代谢研究中的应用。
DOI：
10.1159/000411233
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发表时间：
1985
影响因子：
--
通讯作者：
Segal,S
中科院分区：
文献类型：
--
作者：
Yudkoff,M;Nissim,I;Pleasure,D;Hummeler,K;Segal,S
利用氮的同位素进行新陈代谢研究一直很难进行。放射性物种13N的半衰期非常短(10分钟)，因此必须在使用地点生产。短的半衰期也要求实验的持续时间短。尽管有这些限制，利用13N的研究促进了我们对氮代谢的了解。一个例子是Cooper等人的工作[1]，他们证明了13NH3在注射到人体内后在大脑中的快速定位。更丰富、更容易获得的是稳定同位素15N。在氮代谢研究中更广泛地使用这种物种的一个例子是需要质谱仪，这是一种复杂而昂贵的仪器，以定量15N同位素丰度。此外，质谱学，特别是同位素比质谱仪的样品制备也比较复杂。尽管有这些考虑，15N在生物研究中已经使用了近50年。这项工作的一个重要例子是Berl等人[2]的研究，他们给猫注射了15NH4Cl，并测定了大脑氨基酸中15N的同位素丰度。皮茨等人[3]通过长期给予[酰胺15N]谷氨酰胺，证明了谷氨酰胺作为肾氨氮前体的重要性。
Metabolic studies with isotopes of nitrogen always have been difficult to perform. The radioactive species, 13N, has a very short (10 min) half-life and therefore must be produced at the site of usage. The short half-life also requires that experiments be of short duration. Notwithstanding these limi-tations, studies utilizing 13N have advanced our knowledge of nitrogen metabolism. An example is the work of Cooper et al.[1], who have demon-strated the rapid localization of 13NH3 in the brain after injection into man. Much more abundant and accessible is the stable isotope, 15N. An obs-tacle to the more widespread use of this species in studies of nitrogen metabolism has been the need for mass spectrometry, a complex and expen-sive instrumentation, in order to quantitate 15N isotopic abundance. In ad-dition, the sample preparation for mass spectrometry, particularly isotope ratio mass spectrometry, is complicated. Despite these considerations, 15N has been used in biologic research for almost 50 years. An important exam-ple of such work is the investigation of Berl et al.[2] who administered 15NH4Cl to cats and determined isotopic abundance of 15N in brain amino acids. Pitts et al.[3] documented the importance of glutamine as a precursor for renal ammonia nitrogen by giving [amide 15N] glutamine to chronically