Modifizierung von Argininresten in Pyruvat-Kinase

Abstract
Pyruvate kinase [EC 2.7.1.40] from pig heart is inactivated by the specific arginyl reagent phenylglyoxal. Loss of activity is caused by the reaction of a single molecule of phenylglyoxal per subunit of enzyme. During inactivation 3-6 arginyl residues are modified dependent on the concentration of phenylglyoxal used for modification. Solubility of the protein is reduced by modification. ATP or phosphoenolpyruvate protect against inactivation. A single arginine is less subject to chemical modification in their presence. An arginine may be essential at the substrate binding site. The activating ion K+ does not affect inactivation, whereas Mg2+ diminishes inactivation. Pyruvate kinase from rabbit muscle is modified by phenylglyoxal in a similar manner.