Inhibition of chymotrypsin by diethyl p-nitrophenyl phosphate.

Abstract

CHYMOTRYPSIN displays both esterase and proteolytic activity, and it has recently been shown1 that this enzyme is inhibited by diisopropyl fluorophosphonate and that loss of esterase activity is paralleled by loss of proteolytic activity. Diethyl p-nitrophenyl phosphate (E.600) resembles diisopropyl fluorophosphonate in being a very powerful anticholinesterase. We have found that it will also inhibit chymotrypsin, and have been studying the system chymotrypsin–diethyl p-nitrophenyl phosphate as a convenient model for other esterase systems, since the physical data for this enzyme (purity, molecular weight, etc.) are among the more accurately known.