Table IV.
Substrate preference of invertebrate FDL(-like) hexosaminidases characterized to date in comparison with selected N-glycan modifying hexosaminidases
| Substrate type/complexity | Monosaccharide (aryl)* | Monosaccharide (aryl)* | Biantennary N-glycan | Biantennary N-glycan with or without core fucose | Biantennary N-glycan with two or three core residues |
|---|---|---|---|---|---|
| Substrate | p-nitrophenyl-β-GlcNAc* | p-nitrophenyl-β-GalNAc* | βGNβGN-glycan/GP | GnGn-glycan/GP [±F3 or F6] | GnGnF6Gal- or GnGnF6F3Gal- glycan/GP |
| C. elegans HEX-2 | +1 | +1 | +1 | +1 | + |
| C. elegans HEX-3 | +1 | +1 | +1,6 | +1 | + |
| C. elegans HEX-4 | +1 | +1 | +1 | − | − |
| D. melanogaster FDL | +2 | + | − | +1 | + |
| A. mellifera FDL | + | + | − | + | + |
| C. elegans HEX-51 | + | + | + | − | n/d |
| B. mori FDL3 | + | n/d | n/d | + | n/d |
| O. furnacalis FDL5 | + | + | n/d | + | n/d |
| S. frugiperda FDL4 | + | n/d | n/d | + | n/d |
The analyses performed in this study are labeled with grey background. The structures, which are known or expected to be biologically relevant substrates for the tested enzymes, are labeled with darker grey background. *, non-natural substrate; n/d, not determined; “+”, activity detected; “−”, activity not detected; GP, glycopeptide.
1(Gutternigg et al. 2007); 2(Léonard et al. 2006); 3(Nomura et al. 2010); 4(Geisler et al. 2012); 5(Huo et al. 2013); 6Activity of CeHEX-3 toward dabsylated βGNβGN-glycopeptide was previously not detected when using P. pastoris culture supernatants (Gutternigg et al. 2007).