Extension of the in-gel release method for structural analysis of neutral and sialylated N-linked glycans to the analysis of sulfated glycans: Application to the glycans from bovine thyroid-stimulating hormone

This paper reports an extension of the in-gel technique for releasing N-lin ked glycans from glycoproteins for analysis by matrix-assisted laser desorp tion/ionization (MALDI) mass spectrometry reported by B. Kuster, S. F. Whee ler, A. P. Hunter, R. A. Dwek, and D. J. Harvey (1997, Anal. Biochem. 250, 82-101) to allow it to be used for sulfated glycans. The method was used to identify N-linked glycans from bovine thyroid-stimulating hormone. Followi ng glycan release, either in gel or in solution, the glycans were fractiona ted directly with a porous graphatized carbon column. The sulfated glycans were examined by MALDI mass spectrometry in negative ion mode with D-arabin osazone as the matrix and both neutral and acidic glycans were examined in positive ion mode from 2,5-dihydroxybenzoic acid. Negative ion post-source decay spectra were also obtained. Twenty-two neutral and fifteen sulfated N -linked glycans were identified and it was shown that negligible loss of su lfate groups occurred even though these groups are often readily lost durin g MA-LDI analysis. The glycans were mainly sulfated hybrid and biantennary complex structures. Negative ion post-source decay and positive ion collisi on-induced fragmentation spectra were obtained. (C) 2001 Academic Press.