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Updated: Aug 30, 2026

Production and Testing of Antimicrobial Peptides and Their Mimics
Published on: April 10, 2026
New antimicrobial cystatin C-based peptide active against gram-positive bacterial pathogens, including
Aftab Jasir1, Franciszek Kasprzykowski, Regina Kasprzykowska
1Department of Clinical Chemistry, University Hospital, Lund, Sweden.
Abstract:
We describe the synthesis and antibacterial properties of a novel antimicrobial peptidyl derivative, (2S)-2-(Nalpha-benzyloxycarbonyl-arginyl-leucylamido-1-[(E)-cinnamoylamido]-3-methylbutane, structurally based upon the inhibitory centre of the human cysteine protease inhibitor, cystatin C. The derivative, here called Cystapep 1, displayed antibacterial activity against several clinically important gram-positive bacteria. It displayed minimal inhibitory and bactericidal concentrations of about 16 microg/ml for both Staphylococcus aureus and Streptococcus pyogenes. In radial agar diffusion assays, groups A, B, C and G streptococci as well as staphylococci were generally susceptible to the action of Cystapep 1, whereas pneumococci and enterococci were less susceptible. No activity against gram-negative bacteria was observed. Cystapep 1 also showed high activity against methicillin-resistant S. aureus (MRSA) and multiantibiotic-resistant coagulase-negative staphylococci (CNS), suggesting that its mechanism of action differs from those of most currently used antibiotics.
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