Fluorescent-labelled aprotinin: A new reagent for the histochemical detection of acid mucosubstances

Abstract

Aprotinin (Trasylol®), a polypeptide protease inhibitor from bovine organs, has been labelled with fluorescein isothiocyanate to produce a fluorecent conjugate (FLA). The conjugate has been applied to paraffin sections of rat tissues and has been shown to act as a specific fluorochrome for acidic mucosubstances. There is reason to believe that FLA stains carbohydrates which owe their acidity to the presence of carboxyl groups. The histochemical findings are described and discussed and it is also suggested that attachment of aprotinin to extracellular polysaccharides in vivo may limit the therapeutic usefulness of the drug. © 1973 Springer-Verlag.