title: Interaction of a trypsin-like enzyme of Porphyromonas gingivalis W83 with antithrombin III.
abstract: We have previously observed that trypsin-like activity in Porphyromonas gingivalis culture supernatants is inhibitable by the plasma arg-serpin antithrombin III (ATIII). This report demonstrates that a partially purified P. gingivalis trypsin-like enzyme (M(r) 47,000) is inhibited by ATIII with an association rate constant (k(ass)) of 5.65 x 10(4) M-1 s-1 but does not form SDS-stable complexes. Heparin enhances the k(ass) and stabilizes the complexes but in either case such inhibition is temporary and results in ATIII inactivation by reactive centre proteolysis between R393-S394. In the absence of heparin this is accompanied by N-terminal cleavage between K39-I40.
authors: MRC Dental Research Unit, London Hospital Medical College, UK.
authors: M A
authors: MA
authors: Curtis
authors: J M
authors: JM
authors: Slaney
authors: R J
authors: RJ
authors: Carman
authors: P A
authors: PA
authors: Pemberton
mesh_terms: D000595:Amino Acid Sequence; D000990:Antithrombin III / Q000187:drug effects*; D001426:Bacterial Proteins; D003546:Cysteine Endopeptidases; D004795:Enzyme Stability; D006089:Gram-Negative Anaerobic Bacteria / Q000201:enzymology*; D006493:Heparin / Q000494:pharmacology; D008954:Models, Biological; D008969:Molecular Sequence Data; D014357:Trypsin / Q000187:drug effects / Q000302:isolation & purification* / Q000378:metabolism
chemical_list: D001426:Bacterial Proteins; D000990:Antithrombin III; D006493:Heparin; D014357:Trypsin; D003546:Cysteine Endopeptidases; C078912:prtT protein, Porphyromonas gingivalis