Histochemical Demonstration of Non-specific Esterase in Mast Cells of the Albino Rat with Properties Similar to Mast Cell Enzyme activated in Anaphylaxis

Abstract

RECENT investigations suggest that release of histamine from isolated mast cells of the albino rat by an antigen–antibody reaction is due to an enzymatic process^1,2. Further experiments with inhibitors which are more selective reveal that certain specific chymotrypsin substrates or inhibitors prevent the reaction, whereas substrates and inhibitors of carboxypeptidase, leucine-aminopeptidase or trypsin do not^3–5. Toxic organic phosphorus compounds such as diisopropylfluorophosphate (DFP) or ‘Paraoxon’ also inhibit in relatively high concentration⁶. By virtue of these findings we have concluded that the enzyme responsible for the antigen–antibody reaction of isolated tissue mast cells of the albino rat is a chymotrypsin-like peptidase having pronounced esterolytic properties⁵.