Synthesis of Peptide Chloromethyl Ketones and Examination of Their Inhibitory Effects on Human Spleen Fibrinolytic Proteinase (SFP) and Human Leukocyte Elastase (LE)

Various substrate-derived chloromethyl ketones were synthesized by a conventional method for the purpose of obtaining specific and potent irreversible inhibitors for human spleen fibrinolytic proteinase (SFP) and human leukocyte elastase (LE) in order to compare the properties of SFP with those of LE. It was found that Boc-Ala-Tyr-Leu-Val-CH2Cl among the peptide chloromethyl ketones exhibited the most effective and specific inhibition of SFP and LE. The two enzymes were inhibited by peptide chloromethyl ketones having a Val residue at the C-terminus in a similar manner, demonstrating a similarity between SFP and LE.