Redirecting the Peptide Cleavage Causes Protease Inactivation

Area of Science:

• Biochemistry
• Enzymology
• Medicinal Chemistry

Background:

• Cysteine and serine proteases utilize covalent catalysis for peptide bond cleavage.
• Human cathepsin B is a therapeutically significant cysteine protease.
• Existing protease inhibitors often target active sites but may not achieve irreversible inhibition.

Purpose of the Study:

• To design novel peptidomimetics targeting human cathepsin B.
• To investigate a unique mechanism of enzyme inactivation.
• To explore a new avenue for covalent drug development.

Main Methods:

• Design and synthesis of peptidomimetics with N-terminal carbamate warheads.
• Characterization of inhibitor interaction with human cathepsin B.
• Analysis of the catalytic mechanism and resulting enzyme-protease complex.

Main Results:

• Demonstrated a unique redirection of the catalytic event leading to strong enzyme inactivation.
• Developed peptidomimetics that irreversibly inhibit human cathepsin B.
• Showcased carbamate deprotonation by active site thiolate initiating redirected cleavage.

Conclusions:

• A novel mechanism of irreversible protease inhibition was elucidated.
• Tailored peptidomimetics offer a new strategy for targeting cysteine proteases like cathepsin B.
• This work expands the covalent drug space for therapeutic applications.