Degradation of elastin by a cysteine proteinase from Staphylococcus aureus.
Staphylococcus aureus is known to produce three very active extracellular proteinases. One of these enzymes, a cysteine proteinase, after purification to homogeneity was found to degrade insoluble bovine lung elastin at a rate comparable to human neutrophil elastase. This enzyme had no detectable activity against a range of synthetic substrates normally utilized by elastase, chymotrypsin, or trypsin-like proteinases. However, it did hydrolyze the synthetic substrate carbobenzoxy-phenylalanyl-leucyl-glutamyl-p-nitroanilide (Km = 0.5 mM, kcat = 0.16 s-1). The proteolytic activity of the cysteine proteinase was rapidly and efficiently inhibited by alpha 2-macroglobulin and also by the cysteine-specific inhibitor rat T-kininogen (Ki = 5.2 X 10(-7) M). Human kininogens, however, did not inhibit. Human plasma apparently contains other inhibitors of this enzyme, since plasma depleted of alpha 2-macroglobulin retained significant inhibitory capacity. The elastolytic activity of this S. aureus proteinase and its lack of control by human kininogens or cystatin C may explain some of the connective tissue destruction seen in bacterial infections due to this and related organisms such as may occur in septicemia, septic arthritis, and otitis.
Potempa
J
J
Institute of Molecular Biology, Jagiellonian University, Cracow, Poland.
Dubin
A
A
Korzus
G
G
Travis
J
J
D000818:Animals; D003546:Cysteine Endopeptidases / Q000378:metabolism*; D004549:Elastin / Q000378:metabolism*; D004591:Electrophoresis, Polyacrylamide Gel; D006863:Hydrogen-Ion Concentration; D007700:Kinetics; D007704:Kininogens / Q000494:pharmacology; D008744:Methylamines / Q000494:pharmacology; D051381:Rats; D012697:Serine Endopeptidases / Q000378:metabolism; D013211:Staphylococcus aureus / Q000201:enzymology*
D007704:Kininogens; D008744:Methylamines; D004549:Elastin; C027451:methylamine; D012697:Serine Endopeptidases; C028344:glutamyl endopeptidase; D003546:Cysteine Endopeptidases