1-Naphthalenylsulfonyl-Ile-Trp-aldehyde

Cell-permeable and reversible inhibitor of cathepsin L, a lysosomal cysteine protease ( IC₅₀ 1.9 nM). 1-Naphthalenylsulfonyl-IW-CHO inhibited the release of Ca²⁺ and hydroxyproline from bone in an in vitro bone culture system. It should be useful for the treatment of osteoporosis.