A Short Peptide Inhibitor as an Activity-Based Probe for Matriptase-2

Martin Mangold; Michael Gütschow; Marit Stirnberg

doi:10.3390/ph11020049

A Short Peptide Inhibitor as an Activity-Based Probe for Matriptase-2

Pharmaceuticals (Basel). 2018 May 21;11(2):49. doi: 10.3390/ph11020049.

Authors

Martin Mangold¹, Michael Gütschow², Marit Stirnberg³

Affiliations

¹ Pharmaceutical Chemistry I, Pharmaceutical Institute, University of Bonn, Bonn 53113, Germany. martinmangold@uni-bonn.de.
² Pharmaceutical Chemistry I, Pharmaceutical Institute, University of Bonn, Bonn 53113, Germany. guetschow@uni-bonn.de.
³ Pharmaceutical Chemistry I, Pharmaceutical Institute, University of Bonn, Bonn 53113, Germany. marit.stirnberg@web.de.

Abstract

Matriptase-2 is a type II transmembrane serine protease and a key regulator of systemic iron homeostasis. Since the activation mechanism and several features of the physiological role of matriptase-2 are not fully understood, there is strong need for analytical tools to perform tasks such as distinguishing active and inactive matriptase-2. For this purpose we present a short biotinylated peptide derivative with a chloromethyl ketone group, biotin-RQRR-CMK, as an activity-based probe for matriptase-2. Biotin-RQRR-CMK was kinetically characterized and exhibited a second-order rate constant of inactivation (k_inac/K_i) of 10,800 M^−1 s^−1 towards the matriptase-2 activity in the supernatant of transfected human embryonic kidney (HEK) cells. Biotin-RQRR-CMK was able to label active matriptase-2, as visualized in western blot experiments. Pretreatment with aprotinin, an active-site directed inhibitor of serine proteases, protected matriptase-2 from the reaction with biotin-RQRR-CMK.

Keywords: Activity-based probe; matriptase-2; peptide inhibitor.