Santhosh-Kumar C R, Deutsch J C, Hassell K L, Kolhouse N M, Kolhouse J F
Division of Hematology, University of Colorado Health Sciences Center, Denver, USA.
Anal Biochem. 1995 Feb 10;225(1):1-9. doi: 10.1006/abio.1995.1099.
We report a new gas chromatography-mass spectrometry (GC-MS) method of measurement of red blood cell folates utilizing a stable isotope-labeled bacterial synthesized folate internal standard. The GC-MS method exploits the fact that the common feature of all folate molecules is a p-aminobenzoic acid moiety sandwiched between a pteridine ring and a polyglutamate chain of varying length. In this method, red blood cell folates together with a folate internal standard are specifically purified using bovine folate binding protein and the folates are subsequently chemically cleaved to p-aminobenzoic acid, pteridines, and glutamic acids. Since all six carbon atoms of the benzene ring in the p-aminobenzoic acid moiety of the folate internal standard are labeled with [13C], it is possible to use selected ion monitoring and stable isotope dilution GC-MS to quantitate folates. The method appears to be sensitive, specific, and accurate. The method has been applied to generate a reference range of red blood cell folates based on assay of 25 normal individuals.
我们报告了一种新的利用稳定同位素标记的细菌合成叶酸内标来测量红细胞叶酸的气相色谱-质谱联用（GC-MS）方法。该GC-MS方法利用了所有叶酸分子的共同特征，即一个对氨基苯甲酸部分夹在蝶啶环和不同长度的聚谷氨酸链之间。在这种方法中，红细胞叶酸与叶酸内标一起使用牛叶酸结合蛋白进行特异性纯化，随后将叶酸化学裂解为对氨基苯甲酸、蝶啶和谷氨酸。由于叶酸内标的对氨基苯甲酸部分苯环的所有六个碳原子都用[13C]标记，因此可以使用选择离子监测和稳定同位素稀释GC-MS来定量叶酸。该方法似乎灵敏、特异且准确。该方法已应用于基于对25名正常个体的检测来生成红细胞叶酸的参考范围。
