Trifluoromethyl ketone inhibitors of fatty acid amide hydrolase: A probe of structural and conformational features contributing to inhibition

Design, synthesis and activity as acid ceramidase inhibitors of 2-oxooctanoyl and N-oleoylethanolamine analogues

“…In a previous article (Bedia et al, 2005) we reported on the aCDase inhibitory activity of ␣-ketoamides of a sphingosine-like long chain base. This result was not unexpected, since aCDase is a cysteine hydrolase (Tsuboi et al, 2005) and several authors have reported that ␣-ketoamides are active-site directed inhibitors of serine and cysteine hydrolases, including fatty acid amide hydrolases (Koutek et al, 1994;De Petrocellis et al, 1997;Deutsch et al, 1997;Bisogno et al, 1998;Boger et al, 1999Boger et al, , 2000Vandevoorde et al, 2003). Inhibition by these compounds occurs by reaction of the electron deficient ␣-carbonyl group with the active-site nucleophilic amino acid to form an hemiacetal intermediate, which mimics the reaction transition state.…”

“…As discussed in a previous article (Bedia et al, 2005), assuming that ceramidase inhibition by ␣-ketoamides occurs at the enzyme active centre (Koutek et al, 1994;De Petrocellis et al, 1997;Deutsch et al, 1997;Bisogno et al, 1998;Boger et al, 1999Boger et al, , 2000Vandevoorde et al, 2003), and considering the structural requirement of nCDase for substrates with long chain N-acyl groups (Usta et al, 2001), the ␣-oxooctanamide unit is too short for the appropriate binding needed for inhibition. Besides the presence of the N-2-oxooctanoyl group, the absence of the C3-OH function in compounds 1-11 may further reduce their enzyme affinity, since this secondary hydroxyl group is also important for nCDase activity (Usta et al, 2001).…”

Chemical Probes of Endocannabinoid Metabolism

“…Early FAAH inhibitors included the general serine protease inhibitor phenylmethylsulfonyl fluoride (PMSF) (Desarnaud et al, 1995) and fatty acid derivatives of sulfonylfluorides (Deutsch et al, 1997a), trifluoromethyl ketones (Koutek et al, 1994;Boger et al, 1999), and fluorophosphonates (Deutsch et al, 1997b). Although these first-generation FAAH inhibitors proved invaluable for biochemical and structural studies of FAAH in Endocannabinoid Hydrolase Inhibitors vitro (Bracey et al, 2002), they lacked the selectivity to be used to probe FAAH function in vivo.…”

Structure-guided inhibitor design for human FAAH by interspecies active site conversion

“…These enzymes, which span all kingdoms of life, use an unusual Ser-Ser-Lys catalytic triad (21,22) to hydrolyze amide bonds on a wide range of small-molecule substrates. Despite their atypical catalytic mechanism, amidase signature enzymes are inactivated by general classes of serine hydrolase inhibitors [e.g., trifluoromethyl ketones (23,24), fluorophosphonates (25), ␣-ketoheterocycles (26), carbamates (8,27)]. First-generation FAAH inhibitors, such as methyl arachidonyl fluorophosphonate (MAFP) (25), were substrate-derived in structure and therefore lack selectivity for FAAH relative to other lipid hydrolases.…”