Preparations of research quantities of gangliosides having homogeneous sphingosine base as well as a homogeneous N-fatty acyl group and their corresponding ganglioside oligosaccharides are best accomplished by one of three methodologies, which varies according to the specific ganglioside or ganglioside oligosaccharide, and reflects the feasibility of isolation from biological sources relative to the practicality of total synthesis. Two methodologies arecurrently being explored: (1) chemical total synthesis, and (2) combined cherruical synthesis andenzymatic approach utilizing sialyltransferases. During the past academic year , Prof Cathy Costello and her staff at the BUSM Mass Spectrometry Resource have run a number of mass spectral analyses of ganglioside samples that were submitted from our research related to chemical and chemo-enzymatic preparations of gangliosides and their binding to cholera toxin (NIH M[L 57405). Three intermediates in the chemo-enzymatic synthesis of ganglioside GM3 were analyzed by electrospray mass spectrometry. Since enzyme-assisted glycosidic couplings are only run on 10 mg scales, the mass spectral analyses of small (ug) samples provides extremely useful structural data that supplements nuclear magnetic resonance analyses. Synthetic ganglioside GM3 and material isolated from biological sources were analyzed in their native states by M[ALDI-TOF mass spectrometry. These two samples were also derivatized at the Mass Spectrometry Resource and the permethylated derivatives of both homogeneous synthetic ganglioside GM3 and the native material were also analyzed by MALDI-TOF MS. Prof Costello hasprovided interpretation of all mass spectral data and has brought many literature reports to our attention that have been very helpful to our research.
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