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Identification of sulfoglycolipids from the alga Porphyridium purpureum by matrix‐assisted laser desorption/ionisation quadrupole ion trap time‐of‐flight mass spectrometry
Author(s) -
Naumann Ivonne,
Darsow Kai H.,
Walter Christian,
Lange Harald A.,
Buchholz Rainer
Publication year - 2007
Publication title -
rapid communications in mass spectrometry
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.528
H-Index - 136
eISSN - 1097-0231
pISSN - 0951-4198
DOI - 10.1002/rcm.3190
Subject(s) - chemistry , mass spectrometry , chromatography , matrix assisted laser desorption/ionization , desorption , fatty acid , reflectron , ion trap , time of flight mass spectrometry , ion , ionization , biochemistry , organic chemistry , adsorption
Sulfoglycolipids, isolated from different phototrophic organisms, particularly plants and algae, have already been identified as bioactive compounds. In addition to their antiviral activity their influence on the immune response in mammalian cells is the focus of many studies. For the first time it has been possible to investigate purified sulfoquinovosyldiacylglycerols (SQDGs) from the microalga Porphyridium purpureum by matrix‐assisted laser desorption/ionisation (MALDI) in the negative ion reflectron mode. Thereby, different solid and ionic liquid matrices have been tested to improve signal intensity during the laser ionisation. By using the MALDI Trap time‐of‐flight (ToF) multiple‐stage (MS n ) hybrid mass spectrometer the fatty acid compositions of the SQDGs were analysed by MS, and confirmed by MS 2 and MS 3 experiments. Thereby, hexadecanoic acid (C16:0), octadecadienoic acid (C18:2), eicosatetraenoic acid (C20:4), and eicosapentaenoic acid (C20:5) were detected in the purified fraction of SQDGs. The localisation of hexadecanoic acid (C16:0) at the sn ‐2 position, and unsaturated fatty acids at the sn ‐1 position of the SQDGs, determined by specific enzymatic hydrolysis, marks a procaryotic biosynthesis of SQDGs in the eucaryotic alga cells. Copyright © 2007 John Wiley & Sons, Ltd.