[
  {
    "gtc_id":	"G57321FI",
    "iupac_condensed":	"GalNAc(a1-",
    "motif":	"[{\"label\":\"Tn antigen\",\"id\":\"G57321FI\"}]",
    "subsumption":	null,
    "mass":	null
  },
  {
    "gtc_id":	"G71703UN",
    "iupac_condensed":	"Glc(?1-?)Gal(?1-?)GalNAc(?1-",
    "motif":	null,
    "subsumption":	"Topology",
    "mass":	545.2
  }
]