Tanaka Tamotsu, Tsutsui Hideki, Hirano Kaoru, Koike Tohru, Tokumura Akira, Satouchi Kiyoshi
Department of Applied Biological Science, Fukuyama University, Higashimura, Fukuyama, 729-0292, Japan.
J Lipid Res. 2004 Nov;45(11):2145-50. doi: 10.1194/jlr.D400010-JLR200. Epub 2004 Aug 16.
Lysophosphatidic acid (LPA) is a lipid mediator that may play an important role in wound healing, embryonic development, and progression of cancer. Here, we report a procedure for the quantification of LPA by matrix-assisted laser desorption/ionization time-of-flight mass spectrometry. The method is based on a characteristic mass shift with total charge change (from -2 to +1) of the phosphate species due to 1:1 complexation of LPA(2-) with a dinuclear zinc (II) complex [1,3-bis[bis(pyridin-2-ylmethyl)amino]propan-2-olato dizinc(II) complex; Zn(2)L(3+)] at physiological pH. The monocationic complex LPA(2-)-Zn(2)L(3+) was detected in the positive mode, in which no other signal of cation adducts of LPA(2-) was observed. The detection limit of 18:1 LPA by this method was 0.1 pmol on a sample plate. The intensity ratio of LPA(2-)-Zn(2)L(3+) against an internal standard 17:0 LPA(2-)-Zn(2)L(3+) increased linearly with their molar ratio. Based on the relative intensities of complex ions, we determined the amounts of LPA homologs in an egg white by this method; the results obtained were in good agreement with those by gas liquid chromatography. This sensitive and convenient procedure for LPA-specific detection is useful for the quantification of LPA homologs occurring in biological materials.
溶血磷脂酸（LPA）是一种脂质介质，可能在伤口愈合、胚胎发育和癌症进展中发挥重要作用。在此，我们报告一种通过基质辅助激光解吸/电离飞行时间质谱法定量LPA的方法。该方法基于在生理pH值下，由于LPA(2-)与双核锌（II）配合物[1,3-双[双（吡啶-2-基甲基）氨基]丙烷-2-醇合二锌（II）配合物；Zn(2)L(3+)]以1:1络合，磷酸盐物种的总电荷发生特征性质量位移（从-2变为+1）。在正模式下检测到单阳离子配合物[LPA(2-)-Zn(2)L(3+)]⁺，其中未观察到LPA(2-)的阳离子加合物的其他信号。该方法对18:1 LPA在样品板上的检测限为0.1 pmol。[LPA(2-)-Zn(2)L(3+)]⁺与内标[17:0 LPA(2-)-Zn(2)L(3+)]⁺的强度比随它们的摩尔比呈线性增加。基于络合离子的相对强度，我们用该方法测定了蛋清中LPA同系物的含量；所得结果与气相色谱法的结果高度一致。这种用于LPA特异性检测的灵敏且便捷的方法对于定量生物材料中存在的LPA同系物很有用。
