A fluorescent label for the outer components of the plasma membrane

• 1.

  1. The synthesis of a new fluorescent reagent (4-acetamido,4′-isothiocyanostilbene-2,2′-disulphonic acid) for the specific labelling of the outer components of the plasma membrane is described.

• 2.

  2. The reaction of the reagent with ox erythrocytes is examined. It is concluded that the reagent reacts with a fixed number of sites on the surface of the cell.

• 3.

  3. The problems of designing reagents of this type, and the nature of the reaction between the stilbene isothiocyanate and erythrocytes are discussed.