[Novel peptide inhibitors of the myosin light chain kinase suppress hyperpermeability of vascular endothelium].

The ability of novel cell-permeating peptide molecules derived from the peptide inhibitor of the myosin light chain kinase (MLCK) L-PIK (Arg-Lys-Lys-Tyr-Lys-Tyr-Arg-Arg-Lys) to inhibit this kinase in vitro and attenuate the thrombin-induced hyperpermeability of endothelial cell monolayer in culture has been studied. It was found that the compounds [NalphaMeArg1]-L-PIK and [Cit1]-L-PIK possess the inhibitory activity towards MLCK comparable to that of L-PIK and the ability to suppress the hyperpermeability of endothelium, whereas other modifications of L-PIK were less effective. Thus, among de novo synthesized peptides, [NalphaMeArg1]-L-PIK and [Cit1]-L-PIK demonstrate the inhibitory properties of the original peptide L-PIK and additionally surpass it by stability in blood plasma. These peptides may be used in the design of novel antiedemic drugs.