Protease and elastase of Pseudomonas aeruginosa: inactivation of human plasma alpha 1-proteinase inhibitor

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Abstract
Crystalline elastase of P. aeruginosa may be a very potent inactivator of human plasma .alpha.1-proteinase inhibitor; the enzyme (E) inactivated the inhibitor (I) almost completely within 1 h at 25.degree. C at a molar ratio of E/I = 1:100. The crystalline P. aeruginosa protease inactivated the inhibitor, but 100-fold less. Sodium dodecyl sulfate-polyacrylamide gel electrophoresis indicated that the .alpha.1-proteinase inhibitor inactivated by the elastase and protease showed decreases in MW of approximately 5000 and 10,000, respectively. Regeneration of trypsin was negligible even when bovine trypsin-.alpha.1-proteinase inhibitor complex (E/I = 1.0) was treated with the elastase. The affinity of .alpha.1-proteinase inhibitor to trypsin was much higher than that to elastase. Assuming the pseudomonal proteases are produced and can inactivate .alpha.1-proteinase inhibitor in vivo during pseudomonal diseases, the loss of .alpha.1-proteinase inhibitor activity may permit the endogenous serine proteases to cause tissue destruction.