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Kinetic mechanism for p38 MAP kinase
P V LoGrasso1, B Frantz, A M Rolando
1Department of Molecular Design and Diversity, Merck Research Laboratories, P.O. Box 2000, Rahway, New Jersey 07065, USA. lograsso@merck.com
Biochemistry
|August 26, 1997
Summary
The p38 MAP kinase follows an ordered sequential mechanism, with protein substrate binding before ATP. This unique kinetic mechanism influences enzyme-substrate interactions and inhibitor binding.
Area of Science:
- Biochemistry
- Enzymology
- Signal Transduction
Background:
- p38 MAP kinase is crucial in pro-inflammatory cytokine pathways.
- Its activation and signal transduction are partially understood, but its kinetic mechanism remains largely unknown.
Purpose of the Study:
- To determine the kinetic mechanism of p38 MAP kinase.
- To elucidate the substrate and inhibitor binding interactions.
Main Methods:
- Initial velocity patterns with inhibitors.
- Equilibrium binding studies with a radiolabeled inhibitor.
Main Results:
- p38 MAP kinase exhibits an ordered sequential mechanism, with protein substrate (GST-ATF2) binding prior to ATP.
- Inhibitors showed competitive binding versus ATP and uncompetitive binding versus GST-ATF2.
- ATP binding is dependent on prior protein substrate binding.
Conclusions:
- The determined ordered sequential mechanism for p38 is distinct from other kinases like cAPK.
- This mechanism provides insights into enzyme-substrate and enzyme-inhibitor interactions.