Title : Characterization of the microheterogeneity in
glycoproteins by 500-MHz 1H-NMR spectroscopy of
glycopeptide preparations
Abstract :
- Application to a monofucosylated tetra-antennary glycopeptide fraction from human plasma alpha 1-acid glycoprotein
- Five hundred-MHz 1H-NMR spectroscopy was employed to study a monofucosylated tetra-antennary glycopeptide fraction which was derived from human plasma alpha 1-acid glycoprotein
- This fraction was earlier judged to be homogeneous by 360-MHz 1H-NMR spectroscopic analysis (Fournet, B., Montreuil, J., Strecker, G., Dorland, L., Haverkamp, J., Vliegenthart, J. F. G., Binette, J. P., and Schmid, K. (1978) Biochemistry 17, 5206-5214)
- The combination of the improved resolving power and the enhanced sensitivity of the 500-MHz 1H-NMR spectrometer afforded the elucidation of a new type of microheterogeneity with regard to the position of attachment of Fuc.
- Three isomeric compounds were identified
- The major form contains Fuc alpha-(1 leads to 3) linked to GlcNac 7 of the tetra-antennary structure, as shown earlier
- The two minor compounds, representing new structures, possess Fuc attached in alpha-(1 leads to 3) linkage to GlcNAc 7' or 5'
- It is thus noteworthy that this spectral technique allows elucidation of structures of very closely related carbohydrate chains in a glycopeptide mixture