For example, it has been proposed that low pH in CF airways may mediate the degradation of AMPs via the activation of host proteases, such as cysteine cathepsins, and microbial enzymes, such as aureolysin of S. aureus and elastase of P. aeruginosa, and the immobilization of AMPs through binding to mucins, which are large, anionic glycoproteins and the primary component of mucus. This evidence concerns the gene ADSL and cystic fibrosis.