Heat-labile enterotoxin (LT) is a hetero-oligomeric AB 5 type
enterotoxin composed of a 27 kDa A subunit with toxic ADP ribosyl
transferase activity and a stable noncovalent-linked pentamer of
11.6 kDa B subunits.
The B subunit pentamer mediates holotoxin binding to ganglioside
GM1 on intestinal epithelial cells, with lower affinity for GD1B,
asialoGM1 and lactosylceramide gangliosides.