PEFABLOC, 4-[2-AMINOETHYL]BENZENESULFONYL FLUORIDE, IS A NEW, POTENT NONTOXIC AND IRREVERSIBLE INHIBITOR OF PAF-DEGRADING ACETYLHYDROLASE

We report here that 4-[2-aminoethyl]benzenesulfonyl fluoride (Pefabloc SC, Pefabloc), a new irreversible serine proteinase inhibitor, effici ently inhibits both human and rat platelet activating factor (PAF)-deg rading acetylhydrolase (acetylhydrolase). Indeed, low concentrations o f Pefabloc (0.1 mM) rapidly and totally inactivate both human plasma-, VLDL-, IDL-, LDL- and HDL-associated acetylhydrolase, and in addition , acetylhydrolase synthesized and released by human adherent monocytes in culture, as well as rat brain cytosolic acetylhydrolase. By contra st, Pefabloc only minimally inhibited the phospholipase A(2) (PLA(2)) activity from Naja naja and from porcine pancreas. In addition, Pefabl oc is relatively nontoxic, stable and convenient to use. Henceforth, P efabloc may replace both DFP and PMSF and therefore constitutes a usef ul and valuable tool in future studies of acetylhydrolase.