Open AccessKininogen‐derived peptides for investigating the putative vasoactive properties of human cathepsins K and L
Author(s) -
Desmazes Claire,
Galineau Laurent,
Gauthier Francis,
Brömme Dieter,
Lalmanach Gilles
Publication year - 2003
Publication title -
european journal of biochemistry
Language(s) - English
Resource type - Journals
eISSN - 1432-1033
pISSN - 0014-2956
DOI - 10.1046/j.1432-1033.2003.03382.x
Subject(s) - kininogen , bradykinin , kallidin , cathepsin , chemistry , cathepsin b , biochemistry , cathepsin o , kallikrein , high molecular weight kininogen , kinin , cathepsin l1 , cathepsin a , cathepsin l , cathepsin h , proteases , cathepsin g , proteolysis , enzyme , receptor
Macrophages at an inflammatory site release massive amounts of proteolytic enzymes, including lysosomal cysteine proteases, which colocalize with their circulating, tight‐binding inhibitors (cystatins, kininogens), so modifying the protease/antiprotease equilibrium in favor of enhanced proteolysis. We have explored the ability of human cathepsins B, K and L to participate in the production of kinins, using kininogens and synthetic peptides that mimic the insertion sites of bradykinin on human kininogens. Although both cathepsins processed high‐molecular weight kininogen under stoichiometric conditions, only cathepsin L generated significant amounts of immunoreactive kinins. Cathepsin L exhibited higher specificity constants ( k cat / K m ) than tissue kallikrein (hK1), and similar Michaelis constants towards kininogen‐derived synthetic substrates. A 20‐mer peptide, whose sequence encompassed kininogen residues Ile376 to Ile393, released bradykinin (BK; 80%) and Lys‐bradykinin (20%) when incubated with cathepsin L. By contrast, cathepsin K did not release any kinin, but a truncated kinin metabolite BK(5–9) [FSPFR(385–389)]. Accordingly cathepsin K rapidly produced BK(5–9) from bradykinin and Lys‐bradykinin, and BK(5–8) from des‐Arg9‐bradykinin, by cleaving the Gly384‐Phe385 bond. Data suggest that extracellular cysteine proteases may participate in the regulation of kinin levels at inflammatory sites, and clearly support that cathepsin K may act as a potent kininase.