Irreversible enzyme inhibitors. CXLIV. Proteolytic enzymes. 7. Additional active-site-directed irreversible inhibitors of trypsin derived from m- and p-(phenoxyalkoxy)benzamidines with a terminal sulfonyl fluoride

Abstract

Twenty-four m-and p-(phenoxyalkoxy)beiizamidines bearing a terminal sulfonvl fluoride moiety were synthesized and evaluated as irreversible inhibitors of trypsin; all were excellent reversible inhibitors with K, -0.7-3.0 µ . Eight (2, 3, 5, 6,(19)(20)(21) 24) were excellent active-site-directed irreversible inhibitors when assayed at a K¡ concentration giving 88-100% inactivation. Four (13,(15)(16)(17) showed no irreversible inhibition when assayed at an 8K¡ concentration. The remaining twelve were poor irreversible inhibitors at a >K¡ concentration. One of the excellent irreversible inhibitors of trypsin was p-[p-(p-fluorosulfonyibenzamido)phenoxypropoxy]benzamidine (2), which showed no irreversible inhibition of a related "tryptic" enzyme, namely, thrombin; this specificity is presumably due to the probability that the S02F moiety of 2 forms a covalent bond "outside" the active site where structural differences between trypsin and thrombin are apt to be present. The possibility of design of inhibitors of opposite specificity, that is, inactivation of thrombin with no inactivation of trypsin, by appropriate modification of benzamidine and phenylgttanidine is discussed.

Irreversible Inhibitors of Serine, Cysteine, and Threonine Proteases

“…Sulfonyl fluorides have been widely studied as inhibitors of serine proteases since their initial discovery by Fahrney and Gold in 1963. Sulfonyl fluorides inhibit most serine proteases such as chymotrypsin, − trypsin, , elastase, and complement, coagulation, and fibrinolytic serine proteases . Two well-known sulfonyl fluorides are PMSF ( 88 , Figure ) and 4-(2-aminoethyl)benzenesulfonyl fluoride (AEBSF, 89 , Figure ).…”

Proteolytic truncation of human transthyretin linked to amyloidosis is mediated by a trypsin like enzyme: In vitro demonstration using model peptides

“…This is described as a moderate inhibitor with measured K i ~126 μM (Figure 4). Although our finding of DMF as an inhibitor of trypsin is quite unexpected and accidental but it is not completely unrealistic since compounds containing similar functional moiety such as benzamidines, guanidines and even amides have been reported to inhibit in vitro protease activity of serine proteases like thrombin, trypsin etc [54,55].…”

“…All synthetic hTTR [41][42][43][44][45][46][47][48][49][50][51][52][53][54][55][56][57][58][59][60] peptides namely the wild type P1, along with the mutant peptides S 52 /P (P2), K 48 /A (P3) and T 49 /A(P4) ( Table 1) were analysed based on their 3-D in vacuo generated energy minimised model structures. These structures were obtained by Hyperchem software professional program (v 11.0.…”

Synthetic, Low Molecular Thrombin Inhibitors. A New Concept of Anticoagulants?

“…The reaction sequence involves the initial formation of a reversible enzyme inhibitor complex which is converted into the irreversible complex. Of course, some of the alkylating and acylating substrates would also produce an inhibition from which the enzyme could not rapidly escape [5,8,16,22,37,61,62,67,68,70,76]. The inhibitory effect of aminomethyl and amidino fluorosulfonyl benzenes on thrombin surpassed that of the commonly used organophosphates and chloromethyl ketones [59,82], As shown, the irreversible inhibitors can serve as chemical probes into the con figuration and reactivity of the active site of the thrombin molecule.…”