A fast atom bombardment-mass spectrometric method to quantitate lysophosphatidylserine in rat brain.

Negative-ion fast-atom bombardment mass spectrometry was evaluated as a means for quantitative analysis of individual molecular species of glycerophosphatidylserine (GPS). With 200 ng of 1,2-dipalmitoyl-sn-glycero-3-phosphoserine (GPS di 16:O) as an internal standard, the calibration curve for l-stearoyl-2-oleoyl-sn-glycero-3-phosphoserine (GPS 18:O-18:l) was linear over a range of 50-1000ng (signal-to-noise ratio >4), with a correlation coefficient of 0.998. When the curve was derived from a mixture of GPS molecular species, only a slight variation in the ion intensity ratio of GPS 18:O-18:l to GPS di 16:O occurred. The method provides the possibility of quantifying GPS 18:O-18:l among GPS species in the low nanogram range.Glycerophosphatidylserine (GPS) is an acidic phospholipid naturally present in biological membranes. GPS has been implicated in a number of biological processes, and its pharmacological effects suggest that GPS may act as a regulator of cell-to-cell interaction under physiopathological conditions.'.' In the immune system, GPS and its deacylated derivatives activate rodent mast cells3 and show a selective interaction with rat lymphocyte^.^ In addition, administration of GPS in rat results in a decrease in plasma prolactin levels.' In the central nervous system, the phospholipid increases catecholamine turnover6 and induces the release of acetylcholine from brain ~o r t e x .~ Our interest is focused on a quantitative investigation of the molecular species of GPS, because reports indicated that biological activities of this class of lipid are also dependent on the nature of each of its lipid component^.^,' Reverse-phase high performance liquid chromatography (HPLC) has commonly been used to characterize the molecular species of GPS,". '' but as a method for quantitative analysis it is neither sensitive nor accurate enough. Recently, mass spectrometry has developed into a powerful tool for quantitative analysis of molecular species of phospholipids, and distribution of primary species of brain GPS in the microgram range using liquid chromatography/mass spectrometry has been described.'*, l3 Californium-252 plasma de~orption'~ and desorption chemical ionizati~n'~ have been utilized to identify intact molecules of GPS species. But as methods for quantitative analysis, they are limited by the short duration of observed ions and the lack of reproducibility of molecular ion species and fragment ions. Fast-atom bombardment ionization overcomes these disadvantages. l6 Because of its anionic properties and the amphiphatic character of GPS, we applied negative-ion fast-atom bombardment mass spectrometry (N-FAB-MS) with the surface precipitation te~hnique.'~ This method yielded abundant (and a reproducible intensity signal of) GPS molecular species. The present report *Author to whom correspondence should be addressed. describes a sensitive method for the quantitative analysis of 1-stearoyl-2-oleoyl-sn-glycero-3-phosphoserine :1), a primary molecular species of GPS in most mammalian membranes, by N-FAB-M...

show abstract

Tandem mass spectrometric approach for determining structure of molecular species of aminophospholipids

Chen

1997

Lipids

View full text Add to dashboard Cite

Aminophospholipids, including glycerophosphatidylethanolamine, glycerophosphatidylserine and their Lyso analogous, have been analyzed by positive and negative ion liquid secondary ion ionization coupled to tandem mass spectrometry. The mass spectra of aminophospholipids obtained by tandem mass spectrometers with different configuration (liquid secondary ion-electric-magnetic sector coupled to quadrupole mass analyzer (low-energy collision) or electricmagnetic sector (high-energy collision), as well as electrospray ionization-quadrupole mass analyzer combined with quadrupole mass analyzer (low-energy collision), are compared. The mass spectra produced by low-energy collisionally induced dissociation of the deprotonated molecules from aminophospholipids contain fragment ions for characterizing polar head moieties as well as fatty acid composition and position. The mass spectra generated by high-energy collisionally induced dissociation of both protonated and deprotonated molecules from aminophospholipids show numerous product ions for identifying polar heads, composition, and location of fatty acid chains in molecular species. Triple quadrupole mass spectrometer with electrospray ionization exhibits remarkable superiority in detection sensitivity. Liquid secondary ion with electric-magnetic sector coupled to quadrupole mass analyzer or electric-magnetic sector instrument has the advantage of the capability of properly determining location of fatty acid chains in molecular species. This paper also describes an approach for structurally analyzing aminophospholipid species as 9-fluorenylmethyloxycarbonyl derivatives by positive and negative ion liquid secondary ion mass spectrometry and high-energy collisionally induced dissociation tandem mass spectrometry. It has been found that the derivatives of glycerophosphatidylethanolamine and glycerophosphatidylserine can readily be analyzed by the negative ion liquid secondary ion and tandem mass spectrometric methods. Lipids 32, 85-100 (1997).Aminophospholipids, including glycerophosphatidylethanolamine (GPE), glycerophosphatidylserine (GPS), lysophosphatidylethanolamine (LysoPE) and lysophosphatidylserine (LysoPS), are present as essential components in biological membranes and located preferentially on the inner monolayer. The structural diversity of these lipid molecules is mainly due to (i) different polar head moieties, such as phosphoethanolamine and phosphoserine, linked to phosphate at the sn-3 position of the glycerol backbone; (ii) a variety of diacyl-, alkyl-acyl, and alkenyl-acyl-linked fatty chains esterified at the sn-1 and sn-2 positions, and (iii) location of the double bond(s) (between 1 and 6) within unsaturated fatty chains with a number of carbon atoms (between 14 and 22). Lyso analogous of aminophospholipids, which usually contain only one fatty chain (acyl or alkyl or ether group) at the sn-1 position of the glycerol backbone, are found as minor components in membranes. A number of studies have demonstrated that the phospholipids have played an importa...

show abstract

A fast atom bombardment-mass spectrometric method to quantitate lysophosphatidylserine in rat brain.

Cited by 8 publications

References 16 publications

Fast atom bombardment mass spectrometry of phospholipids

Fast atom bombardment mass spectrometry of phospholipids

Quantitative analysis of 1‐stearoyl‐2‐oleoyl‐sn‐glycero‐3‐phosphoserine by negative‐ion fast‐atom bombardment mass spectrometry

Tandem mass spectrometric approach for determining structure of molecular species of aminophospholipids

Contact Info

Product

Resources

About