Human neutrophil and Pseudomonas aeruginosa elastases were compared for their ability to degrade hog gastric mucin, which was used as a model substrate. P. aeruginosa elastase was more active than neutrophil elastase, and 2 to 10 peptide bonds were hydrolyzed within 5 min. The results demonstrate that both elastases degrade mucins actively at concentrations comparable to physiological levels of...