Elecirophoresis 199 1,12, 96-99 96 saccharide (Figs. and, lane 6). However, a combination of neuraminidase and P-galactosidase gave incomplete digestion and produced three degradation products (Figs. and, lane 8). The band with the lowest mobility represents the original oligosaccharide minus the N-acetylneuraminic acid, as when digested with neuraminidase alone.
The band with the next highest mobility represents the oligosaccharide after the loss of both neuraminic acid and then galactose. This latter band had a mobility slightly greater than the original oligosaccharide band and their difference can be seen by close inspection of lanes and and When both glycosidases were used together, none of the original oligosaccharide was detectable. The degradation product with the highest mobility was the released galactose, which can be seen to align with the band of galactose in the standard mixture. Faint artefactual bands were visible in some gel lanes. One faint band had a mobility close to oligosaccahride I and was an aid in assessing the relative mobilities of oligosaccharide I and its degradation products (see gel lanes (2)-( ) in Figs. and).
These experiments demonstrate both the high resolution ofthe electrophoretic method and how it can be used in the structural analysis of oligosaccharides. Although not all of the saccharides which have been tested are separated (e.g. galactose and mannose) [ 101, the specificities of the enzymes used should enable unequivocal identification of degradation products. The method allows the high resolution analysis of multiple samples in parallel and is relatively rapid, sensitive and inexpensive, and may make glycan structural analysis available more widely. In other work I101 it has been shown that the ANTS derivitisation of small saccharides is virtually quantitative and that approximately 1 pmol can be detected photographically, and as little as 0.2 pmol using the cooled CCD imaging system. The method should, therefore, be useful for the analysis of oligosaccharides from many biological sources.
We wish to thank
Professor C. N . Hales, Dr. C. D . Mackay, Dr. V. E. Urwin and Trinity College, Cambridge fortheirsupport and encouragement. Various aspects of this work are subject to patents (12) which have been either granted or applied for.