[Ultrastructural chemistry of isolated molecules. Application to biological macromolecules. Study of metachromasia]

The ultrastructural chemistry on isolated macromolecules enables to localize chemical function on spread molecules by means of reactions whose product is visible in electron microscopy (metal colloids, lectins, etc.). The reaction of linear polyanions with metachromatic dyes (bifunctional ligands) results in the formation of metachromatic complexes with a periodic structure : ligand molecules are intercalated between the polyanions arranged in parallel arrays; this structure is correlated with the metachromasy.