Studies on the specificity of a serine-esterase inhibitor, phenylmethylsulfonyl fluoride (PMSF)

Abstract

Phenylmethylsulfonyl fluoride (PMSF), a known inhibitor of serine-proteinase activity, was tested for its specificity against a few other hydrolases by conventional procedures using standard substrates. The results show that the compound had no effect on serum leucine and cystine aminopeptidase and calf intestine alkaline phosphatase activity. However, it significantly inhibited phosphodiesterase (Crotalus atrox), trypsin (bovine pancreas), butyrylcholinesterase (horse serum), acid phosphatase (potato), acetylcholinesterase (bovine erythrocytes) and β-glucuronidase (E. coli) activity in a dose-related way and in decreasing order of potency. The study suggests that PMSF is not a selective inhibitor of serine esterases.