Quantitative analysis of lysophosphatidic acid by time-of-flight mass spectrometry using a phosphate-capture molecule.
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.
Department of Applied Biological Science, Fukuyama University, Higashimura, Fukuyama, 729-0292, Japan. tamot@fubac.fukuyama-u.ac.jp
Tamotsu
T
Tanaka
Hideki
H
Tsutsui
Kaoru
K
Hirano
Tohru
T
Koike
Akira
A
Tokumura
Kiyoshi
K
Satouchi
D000818:Animals; D002417:Cattle; D002855:Chromatography, Thin Layer; D018450:Disease Progression; D004305:Dose-Response Relationship, Drug; D004529:Egg White; D008246:Lysophospholipids / Q000032:analysis* / Q000737:chemistry; D013058:Mass Spectrometry / Q000379:methods*; D008956:Models, Chemical; D010710:Phosphates / Q000737:chemistry*; D010940:Plant Proteins / Q000737:chemistry; D019032:Spectrometry, Mass, Matrix-Assisted Laser Desorption-Ionization / Q000379:methods*; D013997:Time Factors; D014945:Wound Healing; D015032:Zinc / Q000737:chemistry
D008246:Lysophospholipids; D010710:Phosphates; D010940:Plant Proteins; D015032:Zinc; C032881:lysophosphatidic acid