Glycobiology and glycomics research using GlyGen — glycan structure lookup by GlyTouCan accession, glycan search by mass/monosaccharide-count/type, glycoprotein glycosylation profiles by UniProt accession, glycosylation-site-level detail (position, flanking sequence, attached glycan, co-located SNVs). Use when someone asks about "what glycans are attached to protein X", "N-linked vs O-linked glycosylation sites", "glycan mass/composition search", "GlyTouCan accession lookup", "glycosylation site at position N", or "which proteins have reported glycosylation in human/mouse". NOT for protein sequence/structure retrieval alone (use tooluniverse-sequence-retrieval or tooluniverse-protein-structure-retrieval), NOT for general small-molecule chemistry (use tooluniverse-chemical-compound-retrieval), NOT for post-translational modifications other than glycosylation (use tooluniverse-protein-modification-analysis).