DNA binds neutrophil elastase and mucus proteinase inhibitor as evidenced by affinity chromatography on elastase-Sepharose, inhibitor-Sepharose and DNA-cellulose. DNA is a potent hyperbolic inhibitor of elastase. The polynucleotide-enzyme complex is partially active on synthetic substrates and on elastin. DNA strongly increases k diss and K i for the inhibition of elastase by mucus proteinase inhibitor. The above effects are all salt-dependent. At physiological ionic strength, DNA is a potent inhibitor of the elastolytic activity of elastase and increases k diss and K i for the elastase-mucus proteinase inhibitor interaction 160-fold and 100-fold, respectively.
