Mechanistic characterization for c-jun-N-Terminal Kinase 1α1

c-jun-N-terininal kinase 1 alpha 1 (JNK1 alpha 1) is a serine/threonine kinase of the mitogen-activated protein (MAP) kinase family that phosphorylates protein transcription factors after activation by a variety of environmental stressors. In this study, the kinetic mechanism for JNK1 alpha 1 phosphorylation of activating transcription factor 2 (ATF2) was determined utilizing steady-state kinetics in the presence and absence of both ATF2 and ATP competitive inhibitors, Data from initial velocity studies were consistent with a sequential mechanism for JNK1 alpha 1. AMP-PCP exhibited competitive inhibition versus ATP and pure noncompetitive inhibition versus ATF2. JIP-1 peptide (RPKRPTTLNLF) was competitive versus ATF2 and mixed noncompetitive Versus ATP. These data suggest that JNK1 alpha 1 proceeded via a random sequential kinetic mechanism with non-interacting ATF2 and ATP Substrate sites. (C) 2008 Elsevier Inc. All rights reserved.