The benzoylarginine peptidase from Treponema denticola (strain ASLM), a human oral spirochaete: evidence for active‐site carboxyl groups

Abstract

The benzoylarginine peptidase of Treponema denticola (strain ASLM; a human oral spirochaete) was progressively and irreversibly inactivated by 1-(ethoxycarbonyl)-2-ethoxy-1, 2-dihydroquinoline, a carboxyl-group reagent. At acidic pH values, reaction of one mole of the modifier per active site of the enzyme resulted in total inactivation of the enzyme. Assuming that this modifier is a specific carboxyl reagent, the data suggest that the inactivation of the T. denticola benzoylarginine peptidase was caused by the modification of one carboxyl group located close to the active site of the enzyme. Results obtained with Woodward's reagent K (N-ethyl-5-phenylisoxazolium 3'-sulphonate) supported these findings. Carbethoxylation with diethylpyrocarbonate effectively inactivated the enzyme, and addition of hydroxylamine at pH 7.0 restored the activity almost totally, suggesting that the pyrocarbonate had reacted with tyrosyl or histidyl residues.

The opdB Locus Encodes the Trypsin-Like Peptidase Activity of Treponema denticola

“…Previous studies characterized a peptidase enzyme from T. denticola that hydrolyzes -X-Arg-p-nitroaniline peptides between arginine and the chromogen (21,23,25). Using Nterminal and internal amino acid sequences determined from the native peptidase (22), we searched six-frame translation products of the preliminary unannotated contigs of the T. denticola genome (http://www.tigr.org) for the gene encoding these peptide sequences.…”

“…A BANA-hydrolyzing peptidase of T. denticola has been isolated, and its biochemical activity has been characterized (21,23,25). The activity profile of the outer membrane-associated enzyme showed it to be an oligopeptidase capable of hydrolyzing ester, amide, and peptide bonds involving the carboxyl group arginine and lysine and, combined with partial peptide sequences (22), suggested that it belongs to the superfamily of prolyl oligopeptidases that includes Escherichia coli oligopeptidase B (EC 3.4.21.83).…”

Spirochetes at the forefront of periodontal infections

“…Some of the other oral treponemes have genes that are almost identical to the prtP and prcA genes that encode dentilisin and the accessory proteins required for its proteolytic activity (23,53). T. denticola and some of the other species also produce a variety of peptidases, the trypsin-like enzyme detected by the BANA test for example, that can contribute to degradation of protein substrates (23,39,84,92,93,96,119,132). Therefore, it is likely that a mixed treponemal flora, even in the absence of other pathogens, would be able to penetrate the gingiva.…”

Antigens of bacteria associated with periodontitis

“…(74) have isolated a trypsin‐like enzyme encoded by the opdB gene from T. denticola strain 35405 that cleaves the synthetic substrate N‐α‐benzoyl‐DL‐arginine‐2‐naphthylamide and natural peptides containing Arg and Lys residues. Trypsin‐like activity has been found not to be responsible for the hydrolysis of a variety of proteins including fibrinogen (208, 209, 211, 260), however, trypsin‐like activity, and not chymotrypsin‐like activity, of T. denticola strain 35405 was found to be important for the degradation of human serum albumin (98).…”