Ultrasensitive internally quenched substrates of human cathepsin L

Monika Lęgowska, Magdalena Wysocka, Timo Burster, Michał Pikuła, Krzysztof Rolka, Adam Lesner

Research output: Contribution to journalArticlepeer-review

9 Citations (Scopus)


Internally quenched cathepsin L (Cat L) substrate ABZ-Bip-Arg-Ala-Gln-Tyr(3-NO2)-NH2 with high specificity constant (kcat/KM=2.6×10(7)M(-1)s(-1)) was synthesized. The resultant compound displayed high selectivity over other members of the cathepsin family (B, S, X, V, C, K, H, F, D, and A). Activity of Cat L at picomolar (pM) concentrations was found using this substrate. Moreover, it was established that the presence of the selective Cat L inhibitor suppressed the proteolysis of the substrate to a non-detectable level. Incubation of the synthesized compound with a cell lysate of healthy and cancer cell lines indicated significant differences in Cat L activity. Based on the obtained results, it is proposed that this substrate could be used for selective monitoring of Cat L activity in biological systems.

Original languageEnglish
Pages (from-to)30-7
Number of pages8
JournalAnalytical Biochemistry
Publication statusPublished - Dec 1 2014
Externally publishedYes


  • Biological Assay
  • Cathepsin L
  • Cathepsins
  • Cell Line
  • Cell Line, Tumor
  • Humans
  • Hydrogen-Ion Concentration
  • Limit of Detection
  • Peptides
  • Substrate Specificity
  • Tyrosine
  • ortho-Aminobenzoates
  • Journal Article
  • Research Support, Non-U.S. Gov't

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