Alkynyl phosphates are potent inhibitors of serine enzyme

Abstract
Propynyl, hexynyl and t‐butylethynyl diethyl phosphates were found to be very powerful covalent inhibitors of serine enzymes. Esterases were inhibited with second‐order rate constants of 107–108 M−1 min−1. Most proteases were inhibited with a rate constant of 104–105 M−1 min−1. By inhibiting chymotrypsin with (3‐14C)‐1‐propynyl diethyl phosphate, it was established that inhibition was caused by binding of the phosphate group to the enzyme active site.