2-Aroylbenzoyl Serine Proteases:  Photoreversible Inhibition or Photoaffinity Labeling?

Abstract

Phenyl esters of 2-benzoylbenzoates were determined to be inhibitors of the serine protease enzymes chymotrypsin and thrombin. Thus, p-guanidinophenyl 2-benzoylbenzoate (1b) inhibited thrombin while the corresponding p-nitrophenyl ester (1a) inhibited chymotrypsin activity. Other p-nitrophenyl esters were prepared that display activity as chymotrypsin inhibitors, three having methoxy group substitution on the benzoyl ring: 2-methoxy (2a), 2,5-dimethoxy (3a), and 2,4,5-trimethoxybenzoyl (4). After incubation with 1b, an acyl thrombin was isolated that showed no lytic activity but which slowly regained activity in pH 7.4 buffer. Irradiation of this acyl enzyme with 366 nm light led to an enzyme that showed no gain of lytic activity over time. Incubation of chymotrypsin with 1a − 3a and 4 led to acyl enzymes which showed no activity but which regained activity slowly. Irradiation of these inactive acyl enzymes with 366 nm light led to a rapid increase in enzyme activity. The formation of acylchymotrypsins that can be photochemically deacylated is suggested by these data. Experiments that relate to the mechanism of enzyme acylation and the subsequent photochemistry of the acylenzymes are reported.

Photoremovable Protecting Groups in Chemistry and Biology: Reaction Mechanisms and Efficacy

“…362 Various esters 200 served as efficient chymotrypsin (a digestive enzyme) inhibitors (Scheme 85). The synthesized acyl-chymotrypsins were found to be stable to hydrolysis from hours to months; a sharp increase of enzyme activity was then observed upon irradiation at 366 nm: up to 80% of the preinhibition activity was recovered.…”

Using photolabile protecting groups for the controlled release of bioactive volatiles

“…As elaborated earlier for the (2-hydroxyphenyl)acrylate derivatives, the 2-aroylbenzoyl group has also successfully been used to photochemically trigger the activity of serine proteases. 59 Irradiation of 10 in a degassed (Ar) solution of benzene/acetonitrile (1 : 1) and in the presence of an amine afforded 3-phenylphthalide and 3,7-dimethyl-2,6-octadienol (geraniol) as the only reaction products on a preparative scale (Scheme 3). 58 The excited triplet state of the precursor reacts by (intermolecular) hydrogen abstraction from the solvent to form an intermediate radical.…”

Potent hypolipidemic activity of mimetic amides of fibrates based on the 2‐methoxy‐4‐(2‐propenyl)phenoxyacetic scaffold

“…7). Starting material 21 was prepared by esterification of acid 22 [Danishefsky et al, 1979], and radical-promoted bromination of the resulting ester 23 [Jones and Porter, 1999], furnishing 21 in 86% overall yield (Fig. 7).…”